diff --git a/classlib/src/main/java/org/teavm/classlib/impl/ServiceLoaderJSSupport.java b/classlib/src/main/java/org/teavm/classlib/impl/ServiceLoaderJSSupport.java
index 4108b9e96..7d67ccef0 100644
--- a/classlib/src/main/java/org/teavm/classlib/impl/ServiceLoaderJSSupport.java
+++ b/classlib/src/main/java/org/teavm/classlib/impl/ServiceLoaderJSSupport.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.classlib.impl;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.Generator;
 import org.teavm.backend.javascript.spi.GeneratorContext;
@@ -27,7 +26,7 @@ public class ServiceLoaderJSSupport implements Generator {
     private static final MethodDescriptor INIT_METHOD = new MethodDescriptor("<init>", void.class);
 
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         var templateFactory = new JavaScriptTemplateFactory(context.getClassLoader(), context.getClassSource());
         var template = templateFactory.createFromResource("org/teavm/classlib/java/util/ServiceLoader.js");
         var information = context.getService(ServiceLoaderInformation.class);
diff --git a/classlib/src/main/java/org/teavm/classlib/impl/reflection/ConverterInjector.java b/classlib/src/main/java/org/teavm/classlib/impl/reflection/ConverterInjector.java
index 9c59dec44..ab91fb440 100644
--- a/classlib/src/main/java/org/teavm/classlib/impl/reflection/ConverterInjector.java
+++ b/classlib/src/main/java/org/teavm/classlib/impl/reflection/ConverterInjector.java
@@ -15,14 +15,13 @@
  */
 package org.teavm.classlib.impl.reflection;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.spi.Injector;
 import org.teavm.backend.javascript.spi.InjectorContext;
 import org.teavm.model.MethodReference;
 
 public class ConverterInjector implements Injector {
     @Override
-    public void generate(InjectorContext context, MethodReference methodRef) throws IOException {
+    public void generate(InjectorContext context, MethodReference methodRef) {
         switch (methodRef.getName()) {
             case "toJava":
             case "fromJava":
diff --git a/classlib/src/main/java/org/teavm/classlib/impl/string/JSStringConstructorGenerator.java b/classlib/src/main/java/org/teavm/classlib/impl/string/JSStringConstructorGenerator.java
index cdedfd357..23da055fc 100644
--- a/classlib/src/main/java/org/teavm/classlib/impl/string/JSStringConstructorGenerator.java
+++ b/classlib/src/main/java/org/teavm/classlib/impl/string/JSStringConstructorGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.classlib.impl.string;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.Generator;
 import org.teavm.backend.javascript.spi.GeneratorContext;
@@ -23,7 +22,7 @@ import org.teavm.model.MethodReference;
 
 public class JSStringConstructorGenerator implements Generator {
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         writer.append(context.getParameterName(0));
         writer.append(".").appendField(JSStringInjector.NATIVE_FIELD).ws().append("=").ws();
         writer.append(context.getParameterName(1)).append(";").softNewLine();
diff --git a/classlib/src/main/java/org/teavm/classlib/impl/string/JSStringInjector.java b/classlib/src/main/java/org/teavm/classlib/impl/string/JSStringInjector.java
index ac6d3a223..67b174b00 100644
--- a/classlib/src/main/java/org/teavm/classlib/impl/string/JSStringInjector.java
+++ b/classlib/src/main/java/org/teavm/classlib/impl/string/JSStringInjector.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.classlib.impl.string;
 
-import java.io.IOException;
 import java.util.function.Function;
 import org.teavm.backend.javascript.ProviderContext;
 import org.teavm.backend.javascript.spi.Injector;
@@ -51,7 +50,7 @@ public class JSStringInjector implements Injector, Function<ProviderContext, Inj
     }
 
     @Override
-    public void generate(InjectorContext context, MethodReference methodRef) throws IOException {
+    public void generate(InjectorContext context, MethodReference methodRef) {
         switch (methodRef.getName()) {
             case "initWithEmptyChars":
                 initWithEmptyChars(context);
@@ -104,13 +103,13 @@ public class JSStringInjector implements Injector, Function<ProviderContext, Inj
         }
     }
 
-    private void initWithEmptyChars(InjectorContext context) throws IOException {
+    private void initWithEmptyChars(InjectorContext context) {
         var writer = context.getWriter();
         context.writeExpr(context.getArgument(0));
         writer.append(".").appendField(NATIVE_FIELD).ws().append("=").ws().append("\"\"");
     }
 
-    private void borrowChars(InjectorContext context) throws IOException {
+    private void borrowChars(InjectorContext context) {
         var writer = context.getWriter();
         context.writeExpr(context.getArgument(0));
         writer.append(".").appendField(NATIVE_FIELD).ws().append("=").ws();
@@ -118,7 +117,7 @@ public class JSStringInjector implements Injector, Function<ProviderContext, Inj
         writer.append(".").appendField(NATIVE_FIELD);
     }
 
-    private void initWithCharArray(InjectorContext context) throws IOException {
+    private void initWithCharArray(InjectorContext context) {
         var writer = context.getWriter();
         context.writeExpr(context.getArgument(0));
         writer.append(".").appendField(NATIVE_FIELD).ws().append("=").ws();
@@ -131,7 +130,7 @@ public class JSStringInjector implements Injector, Function<ProviderContext, Inj
         writer.append(")");
     }
 
-    private void takeCharArray(InjectorContext context) throws IOException {
+    private void takeCharArray(InjectorContext context) {
         var writer = context.getWriter();
         context.writeExpr(context.getArgument(0));
         writer.append(".").appendField(NATIVE_FIELD).ws().append("=").ws();
@@ -140,13 +139,13 @@ public class JSStringInjector implements Injector, Function<ProviderContext, Inj
         writer.append(".data)");
     }
 
-    private void charactersLength(InjectorContext context) throws IOException {
+    private void charactersLength(InjectorContext context) {
         var writer = context.getWriter();
         context.writeExpr(context.getArgument(0));
         writer.append(".").appendField(NATIVE_FIELD).append(".length");
     }
 
-    private void charactersGet(InjectorContext context) throws IOException {
+    private void charactersGet(InjectorContext context) {
         var writer = context.getWriter();
         context.writeExpr(context.getArgument(0));
         writer.append(".").appendField(NATIVE_FIELD).append(".charCodeAt(");
@@ -154,7 +153,7 @@ public class JSStringInjector implements Injector, Function<ProviderContext, Inj
         writer.append(")");
     }
 
-    private void copyCharsToArray(InjectorContext context) throws IOException {
+    private void copyCharsToArray(InjectorContext context) {
         var writer = context.getWriter();
         writer.appendFunction("$rt_stringToCharArray").append("(");
         context.writeExpr(context.getArgument(0));
@@ -171,7 +170,7 @@ public class JSStringInjector implements Injector, Function<ProviderContext, Inj
         writer.append(")");
     }
 
-    private void substringJS(InjectorContext context) throws IOException {
+    private void substringJS(InjectorContext context) {
         var writer = context.getWriter();
         context.writeExpr(context.getArgument(0));
         writer.append(".substring(");
@@ -181,7 +180,7 @@ public class JSStringInjector implements Injector, Function<ProviderContext, Inj
         writer.append(")");
     }
 
-    private void fastCharArray(InjectorContext context) throws IOException {
+    private void fastCharArray(InjectorContext context) {
         var writer = context.getWriter();
         writer.appendFunction("$rt_fastStringToCharArray").append("(");
         context.writeExpr(context.getArgument(0));
@@ -189,44 +188,44 @@ public class JSStringInjector implements Injector, Function<ProviderContext, Inj
         writer.append(")");
     }
 
-    private void nativeString(InjectorContext context) throws IOException {
+    private void nativeString(InjectorContext context) {
         var writer = context.getWriter();
         context.writeExpr(context.getArgument(0));
         writer.append(".").appendField(NATIVE_FIELD);
     }
 
-    private void toLowerCaseJS(InjectorContext context) throws IOException {
+    private void toLowerCaseJS(InjectorContext context) {
         var writer = context.getWriter();
         context.writeExpr(context.getArgument(0));
         writer.append(".toLowerCase()");
     }
 
-    private void toUpperCaseJS(InjectorContext context) throws IOException {
+    private void toUpperCaseJS(InjectorContext context) {
         var writer = context.getWriter();
         context.writeExpr(context.getArgument(0));
         writer.append(".toUpperCase()");
     }
 
-    private void intern(InjectorContext context) throws IOException {
+    private void intern(InjectorContext context) {
         var writer = context.getWriter();
         writer.appendFunction("$rt_intern").append("(");
         context.writeExpr(context.getArgument(0));
         writer.append(")");
     }
 
-    private void stripJS(InjectorContext context) throws IOException {
+    private void stripJS(InjectorContext context) {
         var writer = context.getWriter();
         context.writeExpr(context.getArgument(0));
         writer.append(".trim()");
     }
 
-    private void stripLeadingJS(InjectorContext context) throws IOException {
+    private void stripLeadingJS(InjectorContext context) {
         var writer = context.getWriter();
         context.writeExpr(context.getArgument(0));
         writer.append(".trimStart()");
     }
 
-    private void stripTrailingJS(InjectorContext context) throws IOException {
+    private void stripTrailingJS(InjectorContext context) {
         var writer = context.getWriter();
         context.writeExpr(context.getArgument(0));
         writer.append(".trimEnd()");
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/ClassGenerator.java b/classlib/src/main/java/org/teavm/classlib/java/lang/ClassGenerator.java
index d8dd71f27..619506bc1 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/ClassGenerator.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/ClassGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.classlib.java.lang;
 
-import java.io.IOException;
 import java.util.Set;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.rendering.Precedence;
@@ -43,7 +42,7 @@ public class ClassGenerator implements Generator, Injector, DependencyPlugin {
             new FieldReference(Class.class.getName(), "platformClass");
 
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         switch (methodRef.getName()) {
             case "createMetadata":
                 generateCreateMetadata(context, writer);
@@ -52,7 +51,7 @@ public class ClassGenerator implements Generator, Injector, DependencyPlugin {
     }
 
     @Override
-    public void generate(InjectorContext context, MethodReference methodRef) throws IOException {
+    public void generate(InjectorContext context, MethodReference methodRef) {
         switch (methodRef.getName()) {
             case "newEmptyInstance":
                 context.getWriter().append("new").ws().append("(");
@@ -133,7 +132,7 @@ public class ClassGenerator implements Generator, Injector, DependencyPlugin {
         });
     }
 
-    private void generateCreateMetadata(GeneratorContext context, SourceWriter writer) throws IOException {
+    private void generateCreateMetadata(GeneratorContext context, SourceWriter writer) {
         ReflectionDependencyListener reflection = context.getService(ReflectionDependencyListener.class);
         for (String className : reflection.getClassesWithReflectableFields()) {
             generateCreateFieldsForClass(context, writer, className);
@@ -143,8 +142,7 @@ public class ClassGenerator implements Generator, Injector, DependencyPlugin {
         }
     }
 
-    private void generateCreateFieldsForClass(GeneratorContext context, SourceWriter writer, String className)
-            throws IOException {
+    private void generateCreateFieldsForClass(GeneratorContext context, SourceWriter writer, String className) {
         ReflectionDependencyListener reflection = context.getService(ReflectionDependencyListener.class);
         Set<String> accessibleFields = reflection.getAccessibleFields(className);
 
@@ -178,8 +176,7 @@ public class ClassGenerator implements Generator, Injector, DependencyPlugin {
         writer.outdent().append("];").softNewLine();
     }
 
-    private void generateCreateMethodsForClass(GeneratorContext context, SourceWriter writer, String className)
-            throws IOException {
+    private void generateCreateMethodsForClass(GeneratorContext context, SourceWriter writer, String className) {
         ReflectionDependencyListener reflection = context.getService(ReflectionDependencyListener.class);
         Set<MethodDescriptor> accessibleMethods = reflection.getAccessibleMethods(className);
 
@@ -219,7 +216,7 @@ public class ClassGenerator implements Generator, Injector, DependencyPlugin {
     }
 
     private <T extends MemberReader> void generateCreateMembers(SourceWriter writer, Iterable<T> members,
-            MemberRenderer<T> renderer) throws IOException {
+            MemberRenderer<T> renderer) {
         boolean first = true;
         for (T member : members) {
             if (!first) {
@@ -240,7 +237,7 @@ public class ClassGenerator implements Generator, Injector, DependencyPlugin {
         }
     }
 
-    private void appendProperty(SourceWriter writer, String name, boolean first, Fragment value) throws IOException {
+    private void appendProperty(SourceWriter writer, String name, boolean first, Fragment value) {
         if (!first) {
             writer.append(",").softNewLine();
         }
@@ -248,7 +245,7 @@ public class ClassGenerator implements Generator, Injector, DependencyPlugin {
         value.render();
     }
 
-    private void renderGetter(GeneratorContext context, SourceWriter writer, FieldReader field) throws IOException {
+    private void renderGetter(GeneratorContext context, SourceWriter writer, FieldReader field) {
         writer.append("function(obj)").ws().append("{").indent().softNewLine();
         initClass(context, writer, field);
         writer.append("return ");
@@ -257,7 +254,7 @@ public class ClassGenerator implements Generator, Injector, DependencyPlugin {
         writer.outdent().append("}");
     }
 
-    private void renderSetter(GeneratorContext context, SourceWriter writer, FieldReader field) throws IOException {
+    private void renderSetter(GeneratorContext context, SourceWriter writer, FieldReader field) {
         writer.append("function(obj,").ws().append("val)").ws().append("{").indent().softNewLine();
         initClass(context, writer, field);
         fieldAccess(writer, field);
@@ -267,7 +264,7 @@ public class ClassGenerator implements Generator, Injector, DependencyPlugin {
         writer.outdent().append("}");
     }
 
-    private void renderCallable(GeneratorContext context, SourceWriter writer, MethodReader method) throws IOException {
+    private void renderCallable(GeneratorContext context, SourceWriter writer, MethodReader method) {
         writer.append("function(obj,").ws().append("args)").ws().append("{").indent().softNewLine();
 
         initClass(context, writer, method);
@@ -299,13 +296,13 @@ public class ClassGenerator implements Generator, Injector, DependencyPlugin {
         writer.outdent().append("}");
     }
 
-    private void initClass(GeneratorContext context, SourceWriter writer, MemberReader member) throws IOException {
+    private void initClass(GeneratorContext context, SourceWriter writer, MemberReader member) {
         if (member.hasModifier(ElementModifier.STATIC) && context.isDynamicInitializer(member.getOwnerName())) {
             writer.appendClassInit(member.getOwnerName()).append("();").softNewLine();
         }
     }
 
-    private void fieldAccess(SourceWriter writer, FieldReader field) throws IOException {
+    private void fieldAccess(SourceWriter writer, FieldReader field) {
         if (field.hasModifier(ElementModifier.STATIC)) {
             writer.appendStaticField(field.getReference());
         } else {
@@ -313,7 +310,7 @@ public class ClassGenerator implements Generator, Injector, DependencyPlugin {
         }
     }
 
-    private void boxIfNecessary(SourceWriter writer, ValueType type, Fragment fragment) throws IOException {
+    private void boxIfNecessary(SourceWriter writer, ValueType type, Fragment fragment) {
         boolean boxed = false;
         if (type instanceof ValueType.Primitive) {
             switch (((ValueType.Primitive) type).getKind()) {
@@ -353,7 +350,7 @@ public class ClassGenerator implements Generator, Injector, DependencyPlugin {
         }
     }
 
-    private void unboxIfNecessary(SourceWriter writer, ValueType type, Fragment fragment) throws IOException {
+    private void unboxIfNecessary(SourceWriter writer, ValueType type, Fragment fragment) {
         boolean boxed = false;
         if (type instanceof ValueType.Primitive) {
             switch (((ValueType.Primitive) type).getKind()) {
@@ -392,10 +389,10 @@ public class ClassGenerator implements Generator, Injector, DependencyPlugin {
     }
 
     private interface Fragment {
-        void render() throws IOException;
+        void render();
     }
 
     private interface MemberRenderer<T extends MemberReader> {
-        void render(T member) throws IOException;
+        void render(T member);
     }
 }
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/ClassLoaderNativeGenerator.java b/classlib/src/main/java/org/teavm/classlib/java/lang/ClassLoaderNativeGenerator.java
index 818fa0533..a5cb2d5a1 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/ClassLoaderNativeGenerator.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/ClassLoaderNativeGenerator.java
@@ -23,7 +23,6 @@ import java.util.HashSet;
 import java.util.Properties;
 import java.util.ServiceLoader;
 import java.util.Set;
-import org.apache.commons.io.IOUtils;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.rendering.RenderingUtil;
 import org.teavm.backend.javascript.spi.Injector;
@@ -36,7 +35,7 @@ import org.teavm.model.MethodReference;
 
 public class ClassLoaderNativeGenerator implements Injector {
     @Override
-    public void generate(InjectorContext context, MethodReference methodRef) throws IOException {
+    public void generate(InjectorContext context, MethodReference methodRef) {
         switch (methodRef.getName()) {
             case "supplyResources":
                 generateSupplyResources(context);
@@ -44,7 +43,7 @@ public class ClassLoaderNativeGenerator implements Injector {
         }
     }
 
-    private void generateSupplyResources(InjectorContext context) throws IOException {
+    private void generateSupplyResources(InjectorContext context) {
         SourceWriter writer = context.getWriter();
         writer.append("{").indent();
 
@@ -69,7 +68,7 @@ public class ClassLoaderNativeGenerator implements Injector {
                 }
                 first = false;
                 writer.newLine();
-                byte[] dataBytes = Base64Impl.encode(IOUtils.toByteArray(new BufferedInputStream(input)), true);
+                byte[] dataBytes = Base64Impl.encode(new BufferedInputStream(input).readAllBytes(), true);
                 char[] dataChars = new char[dataBytes.length];
                 for (int i = 0; i < dataBytes.length; ++i) {
                     dataChars[i] = (char) dataBytes[i];
@@ -77,6 +76,8 @@ public class ClassLoaderNativeGenerator implements Injector {
                 RenderingUtil.writeString(writer, resource);
                 writer.append(':').ws();
                 RenderingUtil.writeString(writer, new String(dataChars));
+            } catch (IOException e) {
+                throw new RuntimeException(e);
             }
         }
 
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/DoubleGenerator.java b/classlib/src/main/java/org/teavm/classlib/java/lang/DoubleGenerator.java
index a3e5cb238..6f0b994cc 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/DoubleGenerator.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/DoubleGenerator.java
@@ -15,14 +15,13 @@
  */
 package org.teavm.classlib.java.lang;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.spi.Injector;
 import org.teavm.backend.javascript.spi.InjectorContext;
 import org.teavm.model.MethodReference;
 
 public class DoubleGenerator implements Injector {
     @Override
-    public void generate(InjectorContext context, MethodReference methodRef) throws IOException {
+    public void generate(InjectorContext context, MethodReference methodRef) {
         if (methodRef.getName().equals("doubleEqualsJs")) {
             context.getWriter().appendFunction("$rt_equalDoubles").append("(");
             context.writeExpr(context.getArgument(0));
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/IntegerNativeGenerator.java b/classlib/src/main/java/org/teavm/classlib/java/lang/IntegerNativeGenerator.java
index 6b46faa0c..c292701da 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/IntegerNativeGenerator.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/IntegerNativeGenerator.java
@@ -15,14 +15,13 @@
  */
 package org.teavm.classlib.java.lang;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.spi.Injector;
 import org.teavm.backend.javascript.spi.InjectorContext;
 import org.teavm.model.MethodReference;
 
 public class IntegerNativeGenerator implements Injector {
     @Override
-    public void generate(InjectorContext context, MethodReference methodRef) throws IOException {
+    public void generate(InjectorContext context, MethodReference methodRef) {
         switch (methodRef.getName()) {
             case "divideUnsigned":
                 generateRuntimeCall(context, "$rt_udiv");
@@ -37,7 +36,7 @@ public class IntegerNativeGenerator implements Injector {
     }
 
 
-    private void generateRuntimeCall(InjectorContext context, String name) throws IOException {
+    private void generateRuntimeCall(InjectorContext context, String name) {
         context.getWriter().appendFunction(name).append("(");
         context.writeExpr(context.getArgument(0));
         context.getWriter().append(",").ws();
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/LongNativeGenerator.java b/classlib/src/main/java/org/teavm/classlib/java/lang/LongNativeGenerator.java
index 3655eb87f..5e6ed5b71 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/LongNativeGenerator.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/LongNativeGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.classlib.java.lang;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.Generator;
 import org.teavm.backend.javascript.spi.GeneratorContext;
@@ -23,7 +22,7 @@ import org.teavm.model.MethodReference;
 
 public class LongNativeGenerator implements Generator {
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         switch (methodRef.getName()) {
             case "compare":
                 generateRuntimeCall(context, writer, "Long_compare");
@@ -40,7 +39,7 @@ public class LongNativeGenerator implements Generator {
         }
     }
 
-    private void generateRuntimeCall(GeneratorContext context, SourceWriter writer, String name) throws IOException {
+    private void generateRuntimeCall(GeneratorContext context, SourceWriter writer, String name) {
         writer.append("return ").appendFunction(name).append("(").append(context.getParameterName(1))
                 .append(",").ws()
                 .append(context.getParameterName(2)).append(");").softNewLine();
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/MathNativeGenerator.java b/classlib/src/main/java/org/teavm/classlib/java/lang/MathNativeGenerator.java
index e98f195e4..cd9b1c137 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/MathNativeGenerator.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/MathNativeGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.classlib.java.lang;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.Generator;
 import org.teavm.backend.javascript.spi.GeneratorContext;
@@ -23,7 +22,7 @@ import org.teavm.model.MethodReference;
 
 public class MathNativeGenerator implements Generator {
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         String name = methodRef.getName();
         if (name.endsWith("Impl")) {
             name = name.substring(0, name.length() - 4);
@@ -34,8 +33,7 @@ public class MathNativeGenerator implements Generator {
         function(context, writer, name, methodRef.parameterCount());
     }
 
-    private void function(GeneratorContext context, SourceWriter writer, String name, int paramCount)
-            throws IOException {
+    private void function(GeneratorContext context, SourceWriter writer, String name, int paramCount) {
         writer.append("return ").append("$rt_globals.Math").append(".").append(name).append("(");
         for (int i = 0; i < paramCount; ++i) {
             if (i > 0) {
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/SystemNativeGenerator.java b/classlib/src/main/java/org/teavm/classlib/java/lang/SystemNativeGenerator.java
index 2c9e8f56f..cebe35f7c 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/SystemNativeGenerator.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/SystemNativeGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.classlib.java.lang;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.Generator;
 import org.teavm.backend.javascript.spi.GeneratorContext;
@@ -26,12 +25,12 @@ import org.teavm.model.MethodReference;
 public class SystemNativeGenerator implements Generator {
     private JavaScriptTemplate template;
 
-    public SystemNativeGenerator(JavaScriptTemplateFactory templateFactory) throws IOException {
+    public SystemNativeGenerator(JavaScriptTemplateFactory templateFactory) {
         template = templateFactory.createFromResource("org/teavm/classlib/java/lang/System.js");
     }
 
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         var fragment = template.builder(methodRef.getName()).withContext(context).build();
         fragment.write(writer, 0);
     }
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/reflect/ArrayNativeGenerator.java b/classlib/src/main/java/org/teavm/classlib/java/lang/reflect/ArrayNativeGenerator.java
index 1712cef98..a06e9f329 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/reflect/ArrayNativeGenerator.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/reflect/ArrayNativeGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.classlib.java.lang.reflect;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.Generator;
 import org.teavm.backend.javascript.spi.GeneratorContext;
@@ -26,12 +25,12 @@ import org.teavm.model.MethodReference;
 public class ArrayNativeGenerator implements Generator {
     private JavaScriptTemplate template;
 
-    public ArrayNativeGenerator(JavaScriptTemplateFactory templateFactory) throws IOException {
+    public ArrayNativeGenerator(JavaScriptTemplateFactory templateFactory) {
         template = templateFactory.createFromResource("org/teavm/classlib/java/lang/reflect/Array.js");
     }
 
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         template.builder(methodRef.getName()).withContext(context).build().write(writer, 0);
     }
 }
diff --git a/core/src/main/java/org/teavm/backend/javascript/JavaScriptTarget.java b/core/src/main/java/org/teavm/backend/javascript/JavaScriptTarget.java
index 33fccaac5..acb976669 100644
--- a/core/src/main/java/org/teavm/backend/javascript/JavaScriptTarget.java
+++ b/core/src/main/java/org/teavm/backend/javascript/JavaScriptTarget.java
@@ -458,58 +458,55 @@ public class JavaScriptTarget implements TeaVMTarget, TeaVMJavaScriptHost {
         for (var entry : methodInjectors.entrySet()) {
             renderingContext.addInjector(entry.getKey(), entry.getValue());
         }
-        try {
-            printWrapperStart(sourceWriter);
 
-            for (RendererListener listener : rendererListeners) {
-                listener.begin(renderer, target);
-            }
-            int start = sourceWriter.getOffset();
+        printWrapperStart(sourceWriter);
 
-            renderer.prepare(clsNodes);
-            runtimeRenderer.renderRuntime();
-            sourceWriter.append("var ").append(renderer.getNaming().getScopeName()).ws().append("=").ws()
-                    .append("Object.create(null);").newLine();
-            if (!renderer.render(clsNodes)) {
-                return;
-            }
-            runtimeRenderer.renderHandWrittenRuntime("array.js");
-            renderer.renderStringPool();
-            renderer.renderStringConstants();
-            renderer.renderCompatibilityStubs();
-
-            if (renderer.isLongLibraryUsed()) {
-                runtimeRenderer.renderHandWrittenRuntime("long.js");
-            }
-            if (renderer.isThreadLibraryUsed()) {
-                runtimeRenderer.renderHandWrittenRuntime("thread.js");
-            } else {
-                runtimeRenderer.renderHandWrittenRuntime("simpleThread.js");
-            }
-
-            for (var entry : controller.getEntryPoints().entrySet()) {
-                sourceWriter.append("$rt_exports.").append(entry.getKey()).ws().append("=").ws();
-                var ref = entry.getValue().getMethod();
-                sourceWriter.appendFunction("$rt_mainStarter").append("(").appendMethodBody(ref);
-                sourceWriter.append(");").newLine();
-                sourceWriter.append("$rt_exports.").append(entry.getKey()).append(".").append("javaException")
-                        .ws().append("=").ws().appendFunction("$rt_javaException").append(";").newLine();
-            }
-
-            for (var listener : rendererListeners) {
-                listener.complete();
-            }
-
-            printWrapperEnd(sourceWriter);
-
-            int totalSize = sourceWriter.getOffset() - start;
-            printStats(renderer, totalSize);
-        } catch (IOException e) {
-            throw new RenderingException("IO Error occurred", e);
+        for (RendererListener listener : rendererListeners) {
+            listener.begin(renderer, target);
         }
+        int start = sourceWriter.getOffset();
+
+        renderer.prepare(clsNodes);
+        runtimeRenderer.renderRuntime();
+        sourceWriter.append("var ").append(renderer.getNaming().getScopeName()).ws().append("=").ws()
+                .append("Object.create(null);").newLine();
+        if (!renderer.render(clsNodes)) {
+            return;
+        }
+        runtimeRenderer.renderHandWrittenRuntime("array.js");
+        renderer.renderStringPool();
+        renderer.renderStringConstants();
+        renderer.renderCompatibilityStubs();
+
+        if (renderer.isLongLibraryUsed()) {
+            runtimeRenderer.renderHandWrittenRuntime("long.js");
+        }
+        if (renderer.isThreadLibraryUsed()) {
+            runtimeRenderer.renderHandWrittenRuntime("thread.js");
+        } else {
+            runtimeRenderer.renderHandWrittenRuntime("simpleThread.js");
+        }
+
+        for (var entry : controller.getEntryPoints().entrySet()) {
+            sourceWriter.append("$rt_exports.").append(entry.getKey()).ws().append("=").ws();
+            var ref = entry.getValue().getMethod();
+            sourceWriter.appendFunction("$rt_mainStarter").append("(").appendMethodBody(ref);
+            sourceWriter.append(");").newLine();
+            sourceWriter.append("$rt_exports.").append(entry.getKey()).append(".").append("javaException")
+                    .ws().append("=").ws().appendFunction("$rt_javaException").append(";").newLine();
+        }
+
+        for (var listener : rendererListeners) {
+            listener.complete();
+        }
+
+        printWrapperEnd(sourceWriter);
+
+        int totalSize = sourceWriter.getOffset() - start;
+        printStats(renderer, totalSize);
     }
 
-    private void printWrapperStart(SourceWriter writer) throws IOException {
+    private void printWrapperStart(SourceWriter writer) {
         writer.append("\"use strict\";").newLine();
         printUmdStart(writer);
         writer.append("function($rt_globals,").ws().append("$rt_exports");
@@ -523,7 +520,7 @@ public class JavaScriptTarget implements TeaVMTarget, TeaVMJavaScriptHost {
         return importedModules.get(name);
     }
 
-    private void printUmdStart(SourceWriter writer) throws IOException {
+    private void printUmdStart(SourceWriter writer) {
         writer.append("(function(root,").ws().append("module)").appendBlockStart();
         writer.appendIf().append("typeof define").ws().append("===").ws().append("'function'")
                 .ws().append("&&").ws().append("define.amd)").appendBlockStart();
@@ -562,7 +559,7 @@ public class JavaScriptTarget implements TeaVMTarget, TeaVMJavaScriptHost {
                 .ws();
     }
 
-    private void printWrapperEnd(SourceWriter writer) throws IOException {
+    private void printWrapperEnd(SourceWriter writer) {
         writer.outdent().append("}));").newLine();
     }
 
diff --git a/core/src/main/java/org/teavm/backend/javascript/ast/AstUtil.java b/core/src/main/java/org/teavm/backend/javascript/ast/AstUtil.java
index 93f072bb5..041c82e6d 100644
--- a/core/src/main/java/org/teavm/backend/javascript/ast/AstUtil.java
+++ b/core/src/main/java/org/teavm/backend/javascript/ast/AstUtil.java
@@ -36,9 +36,11 @@ public final class AstUtil {
         return factory.parse(string, null, 0);
     }
 
-    public static AstNode parseFromResources(ClassLoader classLoader, String path) throws IOException {
+    public static AstNode parseFromResources(ClassLoader classLoader, String path) {
         try (var input = classLoader.getResourceAsStream(path)) {
             return parse(new String(input.readAllBytes(), StandardCharsets.UTF_8));
+        } catch (IOException e) {
+            throw new RuntimeException(e);
         }
     }
 }
diff --git a/core/src/main/java/org/teavm/backend/javascript/codegen/SourceWriter.java b/core/src/main/java/org/teavm/backend/javascript/codegen/SourceWriter.java
index 5e1591732..f72c5e74b 100644
--- a/core/src/main/java/org/teavm/backend/javascript/codegen/SourceWriter.java
+++ b/core/src/main/java/org/teavm/backend/javascript/codegen/SourceWriter.java
@@ -42,39 +42,43 @@ public class SourceWriter implements Appendable, LocationProvider {
         this.minified = minified;
     }
 
-    public SourceWriter append(String value) throws IOException {
+    public SourceWriter append(String value) {
         append((CharSequence) value);
         return this;
     }
 
-    public SourceWriter appendBlockStart() throws IOException {
+    public SourceWriter appendBlockStart() {
         return ws().append("{").indent().softNewLine();
     }
 
-    public SourceWriter appendBlockEnd() throws IOException {
+    public SourceWriter appendBlockEnd() {
         return outdent().append("}").softNewLine();
     }
 
-    public SourceWriter appendIf() throws IOException {
+    public SourceWriter appendIf() {
         return append("if").ws().append("(");
     }
 
-    public SourceWriter appendElseIf() throws IOException {
+    public SourceWriter appendElseIf() {
         return outdent().append("}").ws().append("else ").appendIf();
     }
 
-    public SourceWriter appendElse() throws IOException {
+    public SourceWriter appendElse() {
         return outdent().append("}").ws().append("else").appendBlockStart();
     }
 
-    public SourceWriter append(int value) throws IOException {
+    public SourceWriter append(int value) {
         return append(String.valueOf(value));
     }
 
     @Override
-    public SourceWriter append(char value) throws IOException {
+    public SourceWriter append(char value) {
         appendIndent();
-        innerWriter.append(value);
+        try {
+            innerWriter.append(value);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
         if (value == '\n') {
             newLine();
         } else {
@@ -85,13 +89,13 @@ public class SourceWriter implements Appendable, LocationProvider {
     }
 
     @Override
-    public SourceWriter append(CharSequence csq) throws IOException {
+    public SourceWriter append(CharSequence csq) {
         append(csq, 0, csq.length());
         return this;
     }
 
     @Override
-    public SourceWriter append(CharSequence csq, int start, int end) throws IOException {
+    public SourceWriter append(CharSequence csq, int start, int end) {
         int last = start;
         for (int i = start; i < end; ++i) {
             if (csq.charAt(i) == '\n') {
@@ -104,65 +108,69 @@ public class SourceWriter implements Appendable, LocationProvider {
         return this;
     }
 
-    private void appendSingleLine(CharSequence csq, int start, int end) throws IOException {
+    private void appendSingleLine(CharSequence csq, int start, int end) {
         if (start == end) {
             return;
         }
         appendIndent();
         column += end - start;
         offset += end - start;
-        innerWriter.append(csq, start, end);
+        try {
+            innerWriter.append(csq, start, end);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
     }
 
-    public SourceWriter appendClass(String cls) throws IOException {
+    public SourceWriter appendClass(String cls) {
         return appendName(naming.getNameFor(cls));
     }
 
-    public SourceWriter appendClass(Class<?> cls) throws IOException {
+    public SourceWriter appendClass(Class<?> cls) {
         return appendClass(cls.getName());
     }
 
-    public SourceWriter appendField(FieldReference field) throws IOException {
+    public SourceWriter appendField(FieldReference field) {
         return append(naming.getNameFor(field));
     }
 
-    public SourceWriter appendStaticField(FieldReference field) throws IOException {
+    public SourceWriter appendStaticField(FieldReference field) {
         return appendName(naming.getFullNameFor(field));
     }
 
-    public SourceWriter appendMethod(MethodDescriptor method) throws IOException {
+    public SourceWriter appendMethod(MethodDescriptor method) {
         return append(naming.getNameFor(method));
     }
 
-    public SourceWriter appendMethod(String name, Class<?>... params) throws IOException {
+    public SourceWriter appendMethod(String name, Class<?>... params) {
         return append(naming.getNameFor(new MethodDescriptor(name, params)));
     }
 
-    public SourceWriter appendMethodBody(MethodReference method) throws IOException {
+    public SourceWriter appendMethodBody(MethodReference method) {
         return appendName(naming.getFullNameFor(method));
     }
 
-    public SourceWriter appendMethodBody(String className, String name, ValueType... params) throws IOException {
+    public SourceWriter appendMethodBody(String className, String name, ValueType... params) {
         return appendMethodBody(new MethodReference(className, new MethodDescriptor(name, params)));
     }
 
-    public SourceWriter appendMethodBody(Class<?> cls, String name, Class<?>... params) throws IOException {
+    public SourceWriter appendMethodBody(Class<?> cls, String name, Class<?>... params) {
         return appendMethodBody(new MethodReference(cls, name, params));
     }
 
-    public SourceWriter appendFunction(String name) throws IOException {
+    public SourceWriter appendFunction(String name) {
         return append(naming.getNameForFunction(name));
     }
 
-    public SourceWriter appendInit(MethodReference method) throws IOException {
+    public SourceWriter appendInit(MethodReference method) {
         return appendName(naming.getNameForInit(method));
     }
 
-    public SourceWriter appendClassInit(String className) throws IOException {
+    public SourceWriter appendClassInit(String className) {
         return appendName(naming.getNameForClassInit(className));
     }
 
-    private SourceWriter appendName(ScopedName name) throws IOException {
+    private SourceWriter appendName(ScopedName name) {
         if (name.scoped) {
             append(naming.getScopeName()).append(".");
         }
@@ -170,22 +178,30 @@ public class SourceWriter implements Appendable, LocationProvider {
         return this;
     }
 
-    private void appendIndent() throws IOException {
+    private void appendIndent() {
         if (minified) {
             return;
         }
         if (lineStart) {
-            for (int i = 0; i < indentSize; ++i) {
-                innerWriter.append("    ");
-                column += 4;
-                offset += 4;
+            try {
+                for (int i = 0; i < indentSize; ++i) {
+                    innerWriter.append("    ");
+                    column += 4;
+                    offset += 4;
+                }
+                lineStart = false;
+            } catch (IOException e) {
+                throw new RuntimeException(e);
             }
-            lineStart = false;
         }
     }
 
-    public SourceWriter newLine() throws IOException {
-        innerWriter.append('\n');
+    public SourceWriter newLine() {
+        try {
+            innerWriter.append('\n');
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
         column = 0;
         ++line;
         ++offset;
@@ -193,12 +209,16 @@ public class SourceWriter implements Appendable, LocationProvider {
         return this;
     }
 
-    public SourceWriter ws() throws IOException {
+    public SourceWriter ws() {
         if (column >= lineWidth) {
             newLine();
         } else {
             if (!minified) {
-                innerWriter.append(' ');
+                try {
+                    innerWriter.append(' ');
+                } catch (IOException e) {
+                    throw new RuntimeException(e);
+                }
                 column++;
                 offset++;
             }
@@ -206,16 +226,20 @@ public class SourceWriter implements Appendable, LocationProvider {
         return this;
     }
 
-    public SourceWriter tokenBoundary() throws IOException {
+    public SourceWriter tokenBoundary() {
         if (column >= lineWidth) {
             newLine();
         }
         return this;
     }
 
-    public SourceWriter softNewLine() throws IOException {
+    public SourceWriter softNewLine() {
         if (!minified) {
-            innerWriter.append('\n');
+            try {
+                innerWriter.append('\n');
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
             column = 0;
             ++offset;
             ++line;
diff --git a/core/src/main/java/org/teavm/backend/javascript/intrinsics/ref/ReferenceQueueGenerator.java b/core/src/main/java/org/teavm/backend/javascript/intrinsics/ref/ReferenceQueueGenerator.java
index 6866f55c7..25cb3c669 100644
--- a/core/src/main/java/org/teavm/backend/javascript/intrinsics/ref/ReferenceQueueGenerator.java
+++ b/core/src/main/java/org/teavm/backend/javascript/intrinsics/ref/ReferenceQueueGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.backend.javascript.intrinsics.ref;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.Generator;
 import org.teavm.backend.javascript.spi.GeneratorContext;
@@ -27,7 +26,7 @@ public class ReferenceQueueGenerator implements Generator {
     private JavaScriptTemplate template;
 
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         ensureTemplate(context);
         switch (methodRef.getName()) {
             case "<init>":
@@ -39,7 +38,7 @@ public class ReferenceQueueGenerator implements Generator {
         }
     }
 
-    private void ensureTemplate(GeneratorContext context) throws IOException {
+    private void ensureTemplate(GeneratorContext context) {
         if (template == null) {
             template = new JavaScriptTemplateFactory(context.getClassLoader(), context.getClassSource())
                     .createFromResource("org/teavm/classlib/java/lang/ref/ReferenceQueue.js");
diff --git a/core/src/main/java/org/teavm/backend/javascript/intrinsics/ref/WeakReferenceGenerator.java b/core/src/main/java/org/teavm/backend/javascript/intrinsics/ref/WeakReferenceGenerator.java
index f4eece43d..74bdeeedf 100644
--- a/core/src/main/java/org/teavm/backend/javascript/intrinsics/ref/WeakReferenceGenerator.java
+++ b/core/src/main/java/org/teavm/backend/javascript/intrinsics/ref/WeakReferenceGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.backend.javascript.intrinsics.ref;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.Generator;
 import org.teavm.backend.javascript.spi.GeneratorContext;
@@ -27,15 +26,11 @@ public class WeakReferenceGenerator implements Generator {
     private JavaScriptTemplate template;
 
     public WeakReferenceGenerator(JavaScriptTemplateFactory templateFactory) {
-        try {
-            template = templateFactory.createFromResource("org/teavm/classlib/java/lang/ref/WeakReference.js");
-        } catch (IOException e) {
-            throw new RuntimeException(e);
-        }
+        template = templateFactory.createFromResource("org/teavm/classlib/java/lang/ref/WeakReference.js");
     }
 
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         switch (methodRef.getName()) {
             case "<init>":
                 template.builder("init").withContext(context).build().write(writer, 0);
diff --git a/core/src/main/java/org/teavm/backend/javascript/rendering/AstWriter.java b/core/src/main/java/org/teavm/backend/javascript/rendering/AstWriter.java
index 90427ff2c..de80d2a3d 100644
--- a/core/src/main/java/org/teavm/backend/javascript/rendering/AstWriter.java
+++ b/core/src/main/java/org/teavm/backend/javascript/rendering/AstWriter.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.backend.javascript.rendering;
 
-import java.io.IOException;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -155,19 +154,19 @@ public class AstWriter {
         });
     }
 
-    public void print(Object node) throws IOException {
+    public void print(Object node) {
         print((AstNode) node);
     }
 
-    public void print(Object node, int precedence) throws IOException {
+    public void print(Object node, int precedence) {
         print((AstNode) node, precedence);
     }
 
-    public void print(AstNode node) throws IOException {
+    public void print(AstNode node) {
         print(node, PRECEDENCE_COMMA);
     }
 
-    public void print(AstNode node, int precedence) throws IOException {
+    public void print(AstNode node, int precedence) {
         switch (node.getType()) {
             case Token.SCRIPT:
                 print((AstRoot) node);
@@ -305,14 +304,14 @@ public class AstWriter {
         }
     }
 
-    private void print(AstRoot node) throws IOException {
+    private void print(AstRoot node) {
         for (Node child : node) {
             print((AstNode) child);
             writer.softNewLine();
         }
     }
 
-    private void print(Block node) throws IOException {
+    private void print(Block node) {
         writer.append('{').softNewLine().indent();
         for (Node child = node.getFirstChild(); child != null; child = child.getNext()) {
             print((AstNode) child);
@@ -321,7 +320,7 @@ public class AstWriter {
         writer.outdent().append('}');
     }
 
-    private void print(Scope node) throws IOException {
+    private void print(Scope node) {
         var scope = enterScope(node);
         writer.append('{').softNewLine().indent();
         for (Node child = node.getFirstChild(); child != null; child = child.getNext()) {
@@ -332,14 +331,14 @@ public class AstWriter {
         leaveScope(scope);
     }
 
-    private void print(LabeledStatement node) throws IOException {
+    private void print(LabeledStatement node) {
         for (Label label : node.getLabels()) {
             writer.append(label.getName()).append(':').ws();
         }
         print(node.getStatement());
     }
 
-    private void print(BreakStatement node) throws IOException {
+    private void print(BreakStatement node) {
         writer.append("break");
         if (node.getBreakLabel() != null) {
             writer.append(' ').append(node.getBreakLabel().getString());
@@ -347,7 +346,7 @@ public class AstWriter {
         writer.append(';');
     }
 
-    private void print(ContinueStatement node) throws IOException {
+    private void print(ContinueStatement node) {
         writer.append("continue");
         if (node.getLabel() != null) {
             writer.append(' ').append(node.getLabel().getString());
@@ -355,7 +354,7 @@ public class AstWriter {
         writer.append(';');
     }
 
-    private void print(ReturnStatement node) throws IOException {
+    private void print(ReturnStatement node) {
         writer.append("return");
         if (node.getReturnValue() != null) {
             writer.append(' ');
@@ -364,13 +363,13 @@ public class AstWriter {
         writer.append(';');
     }
 
-    private void print(ThrowStatement node) throws IOException {
+    private void print(ThrowStatement node) {
         writer.append("throw ");
         print(node.getExpression());
         writer.append(';');
     }
 
-    private void print(DoLoop node) throws IOException {
+    private void print(DoLoop node) {
         var scope = enterScope(node);
         writer.append("do ").ws();
         print(node.getBody());
@@ -380,7 +379,7 @@ public class AstWriter {
         leaveScope(scope);
     }
 
-    private void print(ForInLoop node) throws IOException {
+    private void print(ForInLoop node) {
         var scope = enterScope(node);
         writer.append("for");
         if (node.isForEach()) {
@@ -395,7 +394,7 @@ public class AstWriter {
         leaveScope(scope);
     }
 
-    private void print(ForLoop node) throws IOException {
+    private void print(ForLoop node) {
         var scope = enterScope(node);
         writer.append("for").ws().append('(');
         print(node.getInitializer());
@@ -408,7 +407,7 @@ public class AstWriter {
         leaveScope(scope);
     }
 
-    private void print(WhileLoop node) throws IOException {
+    private void print(WhileLoop node) {
         var scope = enterScope(node);
         writer.append("while").ws().append('(');
         print(node.getCondition());
@@ -417,7 +416,7 @@ public class AstWriter {
         leaveScope(scope);
     }
 
-    private void print(IfStatement node) throws IOException {
+    private void print(IfStatement node) {
         writer.append("if").ws().append('(');
         print(node.getCondition());
         writer.append(')').ws();
@@ -428,7 +427,7 @@ public class AstWriter {
         }
     }
 
-    private void print(SwitchStatement node) throws IOException {
+    private void print(SwitchStatement node) {
         writer.append("switch").ws().append('(');
         print(node.getExpression());
         writer.append(')').ws().append('{').indent().softNewLine();
@@ -452,7 +451,7 @@ public class AstWriter {
         writer.outdent().append('}');
     }
 
-    private void print(TryStatement node) throws IOException {
+    private void print(TryStatement node) {
         writer.append("try ");
         print(node.getTryBlock());
         for (CatchClause cc : node.getCatchClauses()) {
@@ -471,7 +470,7 @@ public class AstWriter {
         }
     }
 
-    private void print(VariableDeclaration node) throws IOException {
+    private void print(VariableDeclaration node) {
         switch (node.getType()) {
             case Token.VAR:
                 writer.append("var ");
@@ -495,7 +494,7 @@ public class AstWriter {
         }
     }
 
-    private void print(VariableInitializer node) throws IOException {
+    private void print(VariableInitializer node) {
         print(node.getTarget());
         if (node.getInitializer() != null) {
             writer.ws().append('=').ws();
@@ -503,19 +502,19 @@ public class AstWriter {
         }
     }
 
-    private void print(ExpressionStatement node) throws IOException {
+    private void print(ExpressionStatement node) {
         print(node.getExpression());
         writer.append(';');
     }
 
-    protected void print(ElementGet node) throws IOException {
+    protected void print(ElementGet node) {
         print(node.getTarget(), PRECEDENCE_MEMBER);
         writer.append('[');
         print(node.getElement());
         writer.append(']');
     }
 
-    public void print(PropertyGet node) throws IOException {
+    public void print(PropertyGet node) {
         print(node.getLeft(), PRECEDENCE_MEMBER);
         writer.append('.');
         var oldRootScope = rootScope;
@@ -524,7 +523,7 @@ public class AstWriter {
         rootScope = oldRootScope;
     }
 
-    private void print(FunctionCall node, int precedence) throws IOException {
+    private void print(FunctionCall node, int precedence) {
         if (intrinsic(node, precedence)) {
             return;
         }
@@ -556,11 +555,11 @@ public class AstWriter {
         }
     }
 
-    protected boolean intrinsic(FunctionCall node, int precedence) throws IOException {
+    protected boolean intrinsic(FunctionCall node, int precedence) {
         return false;
     }
 
-    private boolean tryJavaInvocation(FunctionCall node) throws IOException {
+    private boolean tryJavaInvocation(FunctionCall node) {
         if (!(node.getTarget() instanceof PropertyGet)) {
             return false;
         }
@@ -593,7 +592,7 @@ public class AstWriter {
         return str.substring("$$JSO$$_".length());
     }
 
-    private void print(ConditionalExpression node, int precedence) throws IOException {
+    private void print(ConditionalExpression node, int precedence) {
         if (precedence < PRECEDENCE_COND) {
             writer.append('(');
         }
@@ -607,7 +606,7 @@ public class AstWriter {
         }
     }
 
-    private void printList(List<? extends AstNode> nodes) throws IOException {
+    private void printList(List<? extends AstNode> nodes) {
         if (nodes == null || nodes.isEmpty()) {
             return;
         }
@@ -618,7 +617,7 @@ public class AstWriter {
         }
     }
 
-    private void print(ArrayComprehension node) throws IOException {
+    private void print(ArrayComprehension node) {
         var scope = enterScope(node);
         writer.append("[");
         for (ArrayComprehensionLoop loop : node.getLoops()) {
@@ -638,7 +637,7 @@ public class AstWriter {
         leaveScope(scope);
     }
 
-    private void print(GeneratorExpression node) throws IOException {
+    private void print(GeneratorExpression node) {
         var scope = enterScope(node);
         writer.append("(");
         for (GeneratorExpressionLoop loop : node.getLoops()) {
@@ -658,17 +657,17 @@ public class AstWriter {
         leaveScope(scope);
     }
 
-    private void print(NumberLiteral node) throws IOException {
+    private void print(NumberLiteral node) {
         writer.append(node.getValue());
     }
 
-    private void print(StringLiteral node) throws IOException {
+    private void print(StringLiteral node) {
         writer.append(node.getQuoteCharacter());
         writer.append(ScriptRuntime.escapeString(node.getValue(), node.getQuoteCharacter()));
         writer.append(node.getQuoteCharacter());
     }
 
-    public void print(Name node, int precedence) throws IOException {
+    public void print(Name node, int precedence) {
         var definingScope = scopeOfId(node.getIdentifier());
         if (rootScope && definingScope == null) {
             var alias = nameMap.get(node.getIdentifier());
@@ -685,17 +684,17 @@ public class AstWriter {
         }
     }
 
-    private void print(RegExpLiteral node) throws IOException {
+    private void print(RegExpLiteral node) {
         writer.append('/').append(node.getValue()).append('/').append(node.getFlags());
     }
 
-    private void print(ArrayLiteral node) throws IOException {
+    private void print(ArrayLiteral node) {
         writer.append('[');
         printList(node.getElements());
         writer.append(']');
     }
 
-    private void print(ObjectLiteral node) throws IOException {
+    private void print(ObjectLiteral node) {
         writer.append('{').ws();
         if (node.getElements() != null && !node.getElements().isEmpty()) {
             print(node.getElements().get(0));
@@ -707,7 +706,7 @@ public class AstWriter {
         writer.ws().append('}');
     }
 
-    private void print(ObjectProperty node) throws IOException {
+    private void print(ObjectProperty node) {
         if (node.isGetterMethod()) {
             writer.append("get ");
         } else if (node.isSetterMethod()) {
@@ -723,7 +722,7 @@ public class AstWriter {
         print(node.getRight());
     }
 
-    private void print(FunctionNode node) throws IOException {
+    private void print(FunctionNode node) {
         var scope = enterScope(node);
         var isArrow = node.getFunctionType() == FunctionNode.ARROW_FUNCTION;
         if (!isArrow) {
@@ -761,7 +760,7 @@ public class AstWriter {
         leaveScope(scope);
     }
 
-    private void print(LetNode node) throws IOException {
+    private void print(LetNode node) {
         var scope = enterScope(node);
         writer.append("let").ws().append('(');
         printList(node.getVariables().getVariables());
@@ -770,11 +769,11 @@ public class AstWriter {
         leaveScope(scope);
     }
 
-    private void print(ParenthesizedExpression node, int precedence) throws IOException {
+    private void print(ParenthesizedExpression node, int precedence) {
         print(node.getExpression(), precedence);
     }
 
-    private void printUnary(UnaryExpression node, int precedence) throws IOException {
+    private void printUnary(UnaryExpression node, int precedence) {
         int innerPrecedence = PRECEDENCE_PREFIX;
 
         if (innerPrecedence > precedence) {
@@ -797,7 +796,7 @@ public class AstWriter {
         }
     }
 
-    private void printUnary(UpdateExpression node, int precedence) throws IOException {
+    private void printUnary(UpdateExpression node, int precedence) {
         int innerPrecedence = node.isPostfix() ? PRECEDENCE_POSTFIX : PRECEDENCE_PREFIX;
 
         if (innerPrecedence > precedence) {
@@ -826,7 +825,7 @@ public class AstWriter {
         }
     }
 
-    private void printInfix(InfixExpression node, int precedence) throws IOException {
+    private void printInfix(InfixExpression node, int precedence) {
         int innerPrecedence = getPrecedence(node.getType());
 
         if (innerPrecedence > precedence) {
diff --git a/core/src/main/java/org/teavm/backend/javascript/rendering/NameEmitter.java b/core/src/main/java/org/teavm/backend/javascript/rendering/NameEmitter.java
index 4b811b7be..162978cc6 100644
--- a/core/src/main/java/org/teavm/backend/javascript/rendering/NameEmitter.java
+++ b/core/src/main/java/org/teavm/backend/javascript/rendering/NameEmitter.java
@@ -15,8 +15,6 @@
  */
 package org.teavm.backend.javascript.rendering;
 
-import java.io.IOException;
-
 public interface NameEmitter {
-    void emit(int precedence) throws IOException;
+    void emit(int precedence);
 }
diff --git a/core/src/main/java/org/teavm/backend/javascript/rendering/Renderer.java b/core/src/main/java/org/teavm/backend/javascript/rendering/Renderer.java
index 3c3a68d1f..2936ce304 100644
--- a/core/src/main/java/org/teavm/backend/javascript/rendering/Renderer.java
+++ b/core/src/main/java/org/teavm/backend/javascript/rendering/Renderer.java
@@ -17,7 +17,6 @@ package org.teavm.backend.javascript.rendering;
 
 import com.carrotsearch.hppc.ObjectIntHashMap;
 import com.carrotsearch.hppc.ObjectIntMap;
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
@@ -181,48 +180,36 @@ public class Renderer implements RenderingManager {
         if (context.getStringPool().isEmpty()) {
             return;
         }
-        try {
-            int start = writer.getOffset();
-            writer.appendFunction("$rt_stringPool").append("([");
-            for (int i = 0; i < context.getStringPool().size(); ++i) {
-                if (i > 0) {
-                    writer.append(',').ws();
-                }
-                RenderingUtil.writeString(writer, context.getStringPool().get(i));
+        int start = writer.getOffset();
+        writer.appendFunction("$rt_stringPool").append("([");
+        for (int i = 0; i < context.getStringPool().size(); ++i) {
+            if (i > 0) {
+                writer.append(',').ws();
             }
-            writer.append("]);").newLine();
-            stringPoolSize = writer.getOffset() - start;
-        } catch (IOException e) {
-            throw new RenderingException("IO error", e);
+            RenderingUtil.writeString(writer, context.getStringPool().get(i));
         }
+        writer.append("]);").newLine();
+        stringPoolSize = writer.getOffset() - start;
     }
 
     public void renderStringConstants() throws RenderingException {
-        try {
-            for (PostponedFieldInitializer initializer : postponedFieldInitializers) {
-                int start = writer.getOffset();
-                writer.appendStaticField(initializer.field).ws().append("=").ws();
-                context.constantToString(writer, initializer.value);
-                writer.append(";").softNewLine();
-                int sz = writer.getOffset() - start;
-                appendClassSize(initializer.field.getClassName(), sz);
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error", e);
+        for (PostponedFieldInitializer initializer : postponedFieldInitializers) {
+            int start = writer.getOffset();
+            writer.appendStaticField(initializer.field).ws().append("=").ws();
+            context.constantToString(writer, initializer.value);
+            writer.append(";").softNewLine();
+            int sz = writer.getOffset() - start;
+            appendClassSize(initializer.field.getClassName(), sz);
         }
     }
 
     public void renderCompatibilityStubs() throws RenderingException {
-        try {
-            renderJavaStringToString();
-            renderJavaObjectToString();
-            renderTeaVMClass();
-        } catch (IOException e) {
-            throw new RenderingException("IO error", e);
-        }
+        renderJavaStringToString();
+        renderJavaObjectToString();
+        renderTeaVMClass();
     }
 
-    private void renderJavaStringToString() throws IOException {
+    private void renderJavaStringToString() {
         writer.appendClass("java.lang.String").append(".prototype.toString").ws().append("=").ws().append("()")
                 .ws().append("=>").ws().append("{").indent().softNewLine();
         writer.append("return ").appendFunction("$rt_ustr").append("(this);").softNewLine();
@@ -231,7 +218,7 @@ public class Renderer implements RenderingManager {
             .appendClass("java.lang.String").append(".prototype.toString;").softNewLine();
     }
 
-    private void renderJavaObjectToString() throws IOException {
+    private void renderJavaObjectToString() {
         writer.appendClass("java.lang.Object").append(".prototype.toString").ws().append("=").ws()
                 .append("()").ws().append("=>").ws().append("{").indent().softNewLine();
         writer.append("return ").appendFunction("$rt_ustr").append("(")
@@ -240,7 +227,7 @@ public class Renderer implements RenderingManager {
         writer.outdent().append("};").newLine();
     }
 
-    private void renderTeaVMClass() throws IOException {
+    private void renderTeaVMClass() {
         writer.appendClass("java.lang.Object").append(".prototype.__teavm_class__").ws().append("=").ws()
                 .append("function()").ws().append("{").indent().softNewLine();
         writer.append("return ").appendFunction("$dbg_class").append("(this);").softNewLine();
@@ -282,52 +269,48 @@ public class Renderer implements RenderingManager {
     private void renderDeclaration(PreparedClass cls) throws RenderingException {
         ScopedName jsName = naming.getNameFor(cls.getName());
         debugEmitter.addClass(jsName.value, cls.getName(), cls.getParentName());
-        try {
-            List<FieldHolder> nonStaticFields = new ArrayList<>();
-            List<FieldHolder> staticFields = new ArrayList<>();
-            for (FieldHolder field : cls.getClassHolder().getFields()) {
-                if (field.getModifiers().contains(ElementModifier.STATIC)) {
-                    staticFields.add(field);
-                } else {
-                    nonStaticFields.add(field);
-                }
-            }
-
-            if (nonStaticFields.isEmpty() && !cls.getClassHolder().getName().equals("java.lang.Object")) {
-                renderShortClassFunctionDeclaration(cls, jsName);
+        List<FieldHolder> nonStaticFields = new ArrayList<>();
+        List<FieldHolder> staticFields = new ArrayList<>();
+        for (FieldHolder field : cls.getClassHolder().getFields()) {
+            if (field.getModifiers().contains(ElementModifier.STATIC)) {
+                staticFields.add(field);
             } else {
-                renderFullClassFunctionDeclaration(cls, jsName, nonStaticFields);
+                nonStaticFields.add(field);
+            }
+        }
+
+        if (nonStaticFields.isEmpty() && !cls.getClassHolder().getName().equals("java.lang.Object")) {
+            renderShortClassFunctionDeclaration(cls, jsName);
+        } else {
+            renderFullClassFunctionDeclaration(cls, jsName, nonStaticFields);
+        }
+
+        for (FieldHolder field : staticFields) {
+            Object value = field.getInitialValue();
+            if (value == null) {
+                value = getDefaultValue(field.getType());
+            }
+            FieldReference fieldRef = new FieldReference(cls.getName(), field.getName());
+            if (value instanceof String) {
+                context.lookupString((String) value);
+                postponedFieldInitializers.add(new PostponedFieldInitializer(fieldRef, (String) value));
+                value = null;
             }
 
-            for (FieldHolder field : staticFields) {
-                Object value = field.getInitialValue();
-                if (value == null) {
-                    value = getDefaultValue(field.getType());
-                }
-                FieldReference fieldRef = new FieldReference(cls.getName(), field.getName());
-                if (value instanceof String) {
-                    context.lookupString((String) value);
-                    postponedFieldInitializers.add(new PostponedFieldInitializer(fieldRef, (String) value));
-                    value = null;
-                }
-
-                ScopedName fieldName = naming.getFullNameFor(fieldRef);
-                if (fieldName.scoped) {
-                    writer.append(naming.getScopeName()).append(".");
-                } else {
-                    writer.append("var ");
-                }
-                writer.append(fieldName.value).ws().append("=").ws();
-                context.constantToString(writer, value);
-                writer.append(";").softNewLine();
+            ScopedName fieldName = naming.getFullNameFor(fieldRef);
+            if (fieldName.scoped) {
+                writer.append(naming.getScopeName()).append(".");
+            } else {
+                writer.append("var ");
             }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+            writer.append(fieldName.value).ws().append("=").ws();
+            context.constantToString(writer, value);
+            writer.append(";").softNewLine();
         }
     }
 
     private void renderFullClassFunctionDeclaration(PreparedClass cls, ScopedName jsName,
-            List<FieldHolder> nonStaticFields) throws IOException {
+            List<FieldHolder> nonStaticFields) {
         boolean thisAliased = false;
         renderFunctionDeclaration(jsName);
         writer.append("()").ws().append("{").indent().softNewLine();
@@ -364,7 +347,7 @@ public class Renderer implements RenderingManager {
         writer.newLine();
     }
 
-    private void renderShortClassFunctionDeclaration(PreparedClass cls, ScopedName jsName) throws IOException {
+    private void renderShortClassFunctionDeclaration(PreparedClass cls, ScopedName jsName) {
         if (jsName.scoped) {
             writer.append(naming.getScopeName()).append(".");
         } else {
@@ -381,34 +364,31 @@ public class Renderer implements RenderingManager {
 
     private void renderMethodBodies(PreparedClass cls) throws RenderingException {
         debugEmitter.emitClass(cls.getName());
-        try {
-            MethodReader clinit = classSource.get(cls.getName()).getMethod(CLINIT_METHOD);
 
-            if (clinit != null && context.isDynamicInitializer(cls.getName())) {
-                renderCallClinit(clinit, cls);
-            }
-            if (!cls.getClassHolder().hasModifier(ElementModifier.INTERFACE)
-                    && !cls.getClassHolder().hasModifier(ElementModifier.ABSTRACT)) {
-                for (PreparedMethod method : cls.getMethods()) {
-                    if (!method.methodHolder.getModifiers().contains(ElementModifier.STATIC)) {
-                        if (method.reference.getName().equals("<init>")) {
-                            renderInitializer(method);
-                        }
+        MethodReader clinit = classSource.get(cls.getName()).getMethod(CLINIT_METHOD);
+
+        if (clinit != null && context.isDynamicInitializer(cls.getName())) {
+            renderCallClinit(clinit, cls);
+        }
+        if (!cls.getClassHolder().hasModifier(ElementModifier.INTERFACE)
+                && !cls.getClassHolder().hasModifier(ElementModifier.ABSTRACT)) {
+            for (PreparedMethod method : cls.getMethods()) {
+                if (!method.methodHolder.getModifiers().contains(ElementModifier.STATIC)) {
+                    if (method.reference.getName().equals("<init>")) {
+                        renderInitializer(method);
                     }
                 }
             }
-
-            for (PreparedMethod method : cls.getMethods()) {
-                renderBody(method);
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
         }
+
+        for (PreparedMethod method : cls.getMethods()) {
+            renderBody(method);
+        }
+
         debugEmitter.emitClass(null);
     }
 
-    private void renderCallClinit(MethodReader clinit, PreparedClass cls)
-            throws IOException {
+    private void renderCallClinit(MethodReader clinit, PreparedClass cls) {
         boolean isAsync = asyncMethods.contains(clinit.getReference());
 
         ScopedName className = naming.getNameFor(cls.getName());
@@ -470,7 +450,7 @@ public class Renderer implements RenderingManager {
         writer.newLine();
     }
 
-    private void renderEraseClinit(PreparedClass cls) throws IOException {
+    private void renderEraseClinit(PreparedClass cls) {
         writer.appendClassInit(cls.getName()).ws().append("=").ws()
                 .appendFunction("$rt_eraseClinit").append("(")
                 .appendClass(cls.getName()).append(");").softNewLine();
@@ -484,25 +464,21 @@ public class Renderer implements RenderingManager {
         ClassMetadataRequirements metadataRequirements = new ClassMetadataRequirements(context.getDependencyInfo());
 
         int start = writer.getOffset();
-        try {
-            writer.appendFunction("$rt_packages").append("([");
-            ObjectIntMap<String> packageIndexes = generatePackageMetadata(classes, metadataRequirements);
-            writer.append("]);").newLine();
 
-            for (int i = 0; i < classes.size(); i += 50) {
-                int j = Math.min(i + 50, classes.size());
-                renderClassMetadataPortion(classes.subList(i, j), packageIndexes, metadataRequirements);
-            }
+        writer.appendFunction("$rt_packages").append("([");
+        ObjectIntMap<String> packageIndexes = generatePackageMetadata(classes, metadataRequirements);
+        writer.append("]);").newLine();
 
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        for (int i = 0; i < classes.size(); i += 50) {
+            int j = Math.min(i + 50, classes.size());
+            renderClassMetadataPortion(classes.subList(i, j), packageIndexes, metadataRequirements);
         }
 
         metadataSize = writer.getOffset() - start;
     }
 
     private void renderClassMetadataPortion(List<PreparedClass> classes, ObjectIntMap<String> packageIndexes,
-            ClassMetadataRequirements metadataRequirements) throws IOException {
+            ClassMetadataRequirements metadataRequirements) {
         writer.appendFunction("$rt_metadata").append("([");
         boolean first = true;
         for (PreparedClass cls : classes) {
@@ -597,7 +573,7 @@ public class Renderer implements RenderingManager {
     }
 
     private ObjectIntMap<String> generatePackageMetadata(List<PreparedClass> classes,
-            ClassMetadataRequirements metadataRequirements) throws IOException {
+            ClassMetadataRequirements metadataRequirements) {
         PackageNode root = new PackageNode(null);
 
         for (PreparedClass classNode : classes) {
@@ -621,8 +597,7 @@ public class Renderer implements RenderingManager {
         return indexes;
     }
 
-    private int writePackageStructure(PackageNode node, int startIndex, String prefix, ObjectIntMap<String> indexes)
-            throws IOException {
+    private int writePackageStructure(PackageNode node, int startIndex, String prefix, ObjectIntMap<String> indexes) {
         int index = startIndex;
         for (PackageNode child : node.children.values()) {
             if (index >= 0) {
@@ -738,7 +713,7 @@ public class Renderer implements RenderingManager {
         return null;
     }
 
-    private void renderInitializer(PreparedMethod method) throws IOException {
+    private void renderInitializer(PreparedMethod method) {
         MethodReference ref = method.reference;
         debugEmitter.emitMethod(ref.getDescriptor());
         ScopedName name = naming.getNameForInit(ref);
@@ -774,7 +749,7 @@ public class Renderer implements RenderingManager {
         return minifying ? RenderingUtil.indexToId(index) : "var_" + index;
     }
 
-    private void renderVirtualDeclarations(Collection<MethodReference> methods) throws IOException {
+    private void renderVirtualDeclarations(Collection<MethodReference> methods) {
         if (methods.stream().noneMatch(this::isVirtual)) {
             writer.append('0');
             return;
@@ -797,14 +772,14 @@ public class Renderer implements RenderingManager {
         writer.append("]");
     }
 
-    private void emitVirtualDeclaration(MethodReference ref) throws IOException {
+    private void emitVirtualDeclaration(MethodReference ref) {
         String methodName = naming.getNameFor(ref.getDescriptor());
         writer.append("\"").append(methodName).append("\"");
         writer.append(",").ws();
         emitVirtualFunctionWrapper(ref);
     }
 
-    private void emitVirtualFunctionWrapper(MethodReference method) throws IOException {
+    private void emitVirtualFunctionWrapper(MethodReference method) {
         if (method.parameterCount() <= 4) {
             writer.appendFunction("$rt_wrapFunction" + method.parameterCount());
             writer.append("(").appendMethodBody(method).append(")");
@@ -834,7 +809,7 @@ public class Renderer implements RenderingManager {
         writer.append(");").ws().append("}");
     }
 
-    private void renderBody(PreparedMethod method) throws IOException {
+    private void renderBody(PreparedMethod method) {
         StatementRenderer statementRenderer = new StatementRenderer(context, writer);
         statementRenderer.setCurrentMethod(method.node);
 
@@ -886,7 +861,7 @@ public class Renderer implements RenderingManager {
         return body instanceof ReturnStatement && ((ReturnStatement) body).getResult() == null;
     }
 
-    private void renderFunctionDeclaration(ScopedName name) throws IOException {
+    private void renderFunctionDeclaration(ScopedName name) {
         if (name.scoped) {
             writer.append(naming.getScopeName()).append(".").append(name.value).ws().append("=").ws();
         }
@@ -896,14 +871,14 @@ public class Renderer implements RenderingManager {
         }
     }
 
-    private void renderAsyncPrologue() throws IOException {
+    private void renderAsyncPrologue() {
         writer.append(context.mainLoopName()).append(":").ws().append("while").ws().append("(true)")
                 .ws().append("{").ws();
         writer.append("switch").ws().append("(").append(context.pointerName()).append(")").ws()
                 .append('{').softNewLine();
     }
 
-    private void renderAsyncEpilogue() throws IOException {
+    private void renderAsyncEpilogue() {
         writer.append("default:").ws().appendFunction("$rt_invalidPointer").append("();").softNewLine();
         writer.append("}}").softNewLine();
     }
@@ -922,112 +897,36 @@ public class Renderer implements RenderingManager {
         }
 
         public void renderNative(PreparedMethod method) {
-            try {
-                this.async = method.async;
-                statementRenderer.setAsync(method.async);
-                method.generator.generate(this, writer, method.reference);
-            } catch (IOException e) {
-                throw new RenderingException("IO error occurred", e);
-            }
+            this.async = method.async;
+            statementRenderer.setAsync(method.async);
+            method.generator.generate(this, writer, method.reference);
         }
 
         @Override
         public void visit(RegularMethodNode method) {
-            try {
-                statementRenderer.setAsync(false);
-                this.async = false;
-                MethodReference ref = method.getReference();
-                for (int i = 0; i < method.getVariables().size(); ++i) {
-                    debugEmitter.emitVariable(new String[] { method.getVariables().get(i).getName() },
-                            statementRenderer.variableName(i));
-                }
-
-                int variableCount = 0;
-                for (VariableNode var : method.getVariables()) {
-                    variableCount = Math.max(variableCount, var.getIndex() + 1);
-                }
-                TryCatchFinder tryCatchFinder = new TryCatchFinder();
-                method.getBody().acceptVisitor(tryCatchFinder);
-                boolean hasTryCatch = tryCatchFinder.tryCatchFound;
-                List<String> variableNames = new ArrayList<>();
-                for (int i = ref.parameterCount() + 1; i < variableCount; ++i) {
-                    variableNames.add(statementRenderer.variableName(i));
-                }
-                if (hasTryCatch) {
-                    variableNames.add("$$je");
-                }
-                if (!variableNames.isEmpty()) {
-                    writer.append("var ");
-                    for (int i = 0; i < variableNames.size(); ++i) {
-                        if (i > 0) {
-                            writer.append(",").ws();
-                        }
-                        writer.append(variableNames.get(i));
-                    }
-                    writer.append(";").softNewLine();
-                }
-
-                statementRenderer.setEnd(true);
-                statementRenderer.setCurrentPart(0);
-
-                if (method.getModifiers().contains(ElementModifier.SYNCHRONIZED)) {
-                    writer.appendMethodBody(NameFrequencyEstimator.MONITOR_ENTER_SYNC_METHOD);
-                    writer.append("(");
-                    appendMonitor(statementRenderer, method);
-                    writer.append(");").softNewLine();
-
-                    writer.append("try").ws().append("{").softNewLine().indent();
-                }
-
-                method.getBody().acceptVisitor(statementRenderer);
-
-                if (method.getModifiers().contains(ElementModifier.SYNCHRONIZED)) {
-                    writer.outdent().append("}").ws().append("finally").ws().append("{").indent().softNewLine();
-
-                    writer.appendMethodBody(NameFrequencyEstimator.MONITOR_EXIT_SYNC_METHOD);
-                    writer.append("(");
-                    appendMonitor(statementRenderer, method);
-                    writer.append(");").softNewLine();
-
-                    writer.outdent().append("}").softNewLine();
-                }
-
-            } catch (IOException e) {
-                throw new RenderingException("IO error occurred", e);
+            statementRenderer.setAsync(false);
+            this.async = false;
+            MethodReference ref = method.getReference();
+            for (int i = 0; i < method.getVariables().size(); ++i) {
+                debugEmitter.emitVariable(new String[] { method.getVariables().get(i).getName() },
+                        statementRenderer.variableName(i));
             }
-        }
 
-        @Override
-        public void visit(AsyncMethodNode methodNode) {
-            threadLibraryUsed = true;
-            try {
-                statementRenderer.setAsync(true);
-                this.async = true;
-                MethodReference ref = methodNode.getReference();
-                for (int i = 0; i < methodNode.getVariables().size(); ++i) {
-                    debugEmitter.emitVariable(new String[] { methodNode.getVariables().get(i).getName() },
-                            statementRenderer.variableName(i));
-                }
-                int variableCount = 0;
-                for (VariableNode var : methodNode.getVariables()) {
-                    variableCount = Math.max(variableCount, var.getIndex() + 1);
-                }
-                List<String> variableNames = new ArrayList<>();
-                for (int i = ref.parameterCount() + 1; i < variableCount; ++i) {
-                    variableNames.add(statementRenderer.variableName(i));
-                }
-                TryCatchFinder tryCatchFinder = new TryCatchFinder();
-                for (AsyncMethodPart part : methodNode.getBody()) {
-                    if (!tryCatchFinder.tryCatchFound) {
-                        part.getStatement().acceptVisitor(tryCatchFinder);
-                    }
-                }
-                boolean hasTryCatch = tryCatchFinder.tryCatchFound;
-                if (hasTryCatch) {
-                    variableNames.add("$$je");
-                }
-                variableNames.add(context.pointerName());
-                variableNames.add(context.tempVarName());
+            int variableCount = 0;
+            for (VariableNode var : method.getVariables()) {
+                variableCount = Math.max(variableCount, var.getIndex() + 1);
+            }
+            TryCatchFinder tryCatchFinder = new TryCatchFinder();
+            method.getBody().acceptVisitor(tryCatchFinder);
+            boolean hasTryCatch = tryCatchFinder.tryCatchFound;
+            List<String> variableNames = new ArrayList<>();
+            for (int i = ref.parameterCount() + 1; i < variableCount; ++i) {
+                variableNames.add(statementRenderer.variableName(i));
+            }
+            if (hasTryCatch) {
+                variableNames.add("$$je");
+            }
+            if (!variableNames.isEmpty()) {
                 writer.append("var ");
                 for (int i = 0; i < variableNames.size(); ++i) {
                     if (i > 0) {
@@ -1036,71 +935,134 @@ public class Renderer implements RenderingManager {
                     writer.append(variableNames.get(i));
                 }
                 writer.append(";").softNewLine();
+            }
 
-                int firstToSave = 0;
-                if (methodNode.getModifiers().contains(ElementModifier.STATIC)) {
-                    firstToSave = 1;
-                }
+            statementRenderer.setEnd(true);
+            statementRenderer.setCurrentPart(0);
+
+            if (method.getModifiers().contains(ElementModifier.SYNCHRONIZED)) {
+                writer.appendMethodBody(NameFrequencyEstimator.MONITOR_ENTER_SYNC_METHOD);
+                writer.append("(");
+                appendMonitor(statementRenderer, method);
+                writer.append(");").softNewLine();
+
+                writer.append("try").ws().append("{").softNewLine().indent();
+            }
+
+            method.getBody().acceptVisitor(statementRenderer);
+
+            if (method.getModifiers().contains(ElementModifier.SYNCHRONIZED)) {
+                writer.outdent().append("}").ws().append("finally").ws().append("{").indent().softNewLine();
+
+                writer.appendMethodBody(NameFrequencyEstimator.MONITOR_EXIT_SYNC_METHOD);
+                writer.append("(");
+                appendMonitor(statementRenderer, method);
+                writer.append(");").softNewLine();
 
-                String popName = minifying ? "l" : "pop";
-                String pushName = minifying ? "s" : "push";
-                writer.append(context.pointerName()).ws().append('=').ws().append("0;").softNewLine();
-                writer.append("if").ws().append("(").appendFunction("$rt_resuming").append("())").ws()
-                        .append("{").indent().softNewLine();
-                writer.append("var ").append(context.threadName()).ws().append('=').ws()
-                        .appendFunction("$rt_nativeThread").append("();").softNewLine();
-                writer.append(context.pointerName()).ws().append('=').ws().append(context.threadName()).append(".")
-                        .append(popName).append("();");
-                for (int i = variableCount - 1; i >= firstToSave; --i) {
-                    writer.append(statementRenderer.variableName(i)).ws().append('=').ws().append(context.threadName())
-                            .append(".").append(popName).append("();");
-                }
-                writer.softNewLine();
                 writer.outdent().append("}").softNewLine();
+            }
+        }
 
-                if (methodNode.getModifiers().contains(ElementModifier.SYNCHRONIZED)) {
-                    writer.append("try").ws().append('{').indent().softNewLine();
+        @Override
+        public void visit(AsyncMethodNode methodNode) {
+            threadLibraryUsed = true;
+            statementRenderer.setAsync(true);
+            this.async = true;
+            MethodReference ref = methodNode.getReference();
+            for (int i = 0; i < methodNode.getVariables().size(); ++i) {
+                debugEmitter.emitVariable(new String[] { methodNode.getVariables().get(i).getName() },
+                        statementRenderer.variableName(i));
+            }
+            int variableCount = 0;
+            for (VariableNode var : methodNode.getVariables()) {
+                variableCount = Math.max(variableCount, var.getIndex() + 1);
+            }
+            List<String> variableNames = new ArrayList<>();
+            for (int i = ref.parameterCount() + 1; i < variableCount; ++i) {
+                variableNames.add(statementRenderer.variableName(i));
+            }
+            TryCatchFinder tryCatchFinder = new TryCatchFinder();
+            for (AsyncMethodPart part : methodNode.getBody()) {
+                if (!tryCatchFinder.tryCatchFound) {
+                    part.getStatement().acceptVisitor(tryCatchFinder);
                 }
-
-                renderAsyncPrologue();
-                for (int i = 0; i < methodNode.getBody().size(); ++i) {
-                    writer.append("case ").append(i).append(":").indent().softNewLine();
-                    if (i == 0 && methodNode.getModifiers().contains(ElementModifier.SYNCHRONIZED)) {
-                        writer.appendMethodBody(NameFrequencyEstimator.MONITOR_ENTER_METHOD);
-                        writer.append("(");
-                        appendMonitor(statementRenderer, methodNode);
-                        writer.append(");").softNewLine();
-                        statementRenderer.emitSuspendChecker();
-                    }
-                    AsyncMethodPart part = methodNode.getBody().get(i);
-                    statementRenderer.setEnd(true);
-                    statementRenderer.setCurrentPart(i);
-                    part.getStatement().acceptVisitor(statementRenderer);
-                    writer.outdent();
+            }
+            boolean hasTryCatch = tryCatchFinder.tryCatchFound;
+            if (hasTryCatch) {
+                variableNames.add("$$je");
+            }
+            variableNames.add(context.pointerName());
+            variableNames.add(context.tempVarName());
+            writer.append("var ");
+            for (int i = 0; i < variableNames.size(); ++i) {
+                if (i > 0) {
+                    writer.append(",").ws();
                 }
-                renderAsyncEpilogue();
+                writer.append(variableNames.get(i));
+            }
+            writer.append(";").softNewLine();
 
-                if (methodNode.getModifiers().contains(ElementModifier.SYNCHRONIZED)) {
-                    writer.outdent().append("}").ws().append("finally").ws().append('{').indent().softNewLine();
-                    writer.append("if").ws().append("(!").appendFunction("$rt_suspending").append("())")
-                            .ws().append("{").indent().softNewLine();
-                    writer.appendMethodBody(NameFrequencyEstimator.MONITOR_EXIT_METHOD);
+            int firstToSave = 0;
+            if (methodNode.getModifiers().contains(ElementModifier.STATIC)) {
+                firstToSave = 1;
+            }
+
+            String popName = minifying ? "l" : "pop";
+            String pushName = minifying ? "s" : "push";
+            writer.append(context.pointerName()).ws().append('=').ws().append("0;").softNewLine();
+            writer.append("if").ws().append("(").appendFunction("$rt_resuming").append("())").ws()
+                    .append("{").indent().softNewLine();
+            writer.append("var ").append(context.threadName()).ws().append('=').ws()
+                    .appendFunction("$rt_nativeThread").append("();").softNewLine();
+            writer.append(context.pointerName()).ws().append('=').ws().append(context.threadName()).append(".")
+                    .append(popName).append("();");
+            for (int i = variableCount - 1; i >= firstToSave; --i) {
+                writer.append(statementRenderer.variableName(i)).ws().append('=').ws().append(context.threadName())
+                        .append(".").append(popName).append("();");
+            }
+            writer.softNewLine();
+            writer.outdent().append("}").softNewLine();
+
+            if (methodNode.getModifiers().contains(ElementModifier.SYNCHRONIZED)) {
+                writer.append("try").ws().append('{').indent().softNewLine();
+            }
+
+            renderAsyncPrologue();
+            for (int i = 0; i < methodNode.getBody().size(); ++i) {
+                writer.append("case ").append(i).append(":").indent().softNewLine();
+                if (i == 0 && methodNode.getModifiers().contains(ElementModifier.SYNCHRONIZED)) {
+                    writer.appendMethodBody(NameFrequencyEstimator.MONITOR_ENTER_METHOD);
                     writer.append("(");
                     appendMonitor(statementRenderer, methodNode);
                     writer.append(");").softNewLine();
-                    writer.outdent().append('}').softNewLine();
-                    writer.outdent().append('}').softNewLine();
+                    statementRenderer.emitSuspendChecker();
                 }
-
-                writer.appendFunction("$rt_nativeThread").append("().").append(pushName).append("(");
-                for (int i = firstToSave; i < variableCount; ++i) {
-                    writer.append(statementRenderer.variableName(i)).append(',').ws();
-                }
-                writer.append(context.pointerName()).append(");");
-                writer.softNewLine();
-            } catch (IOException e) {
-                throw new RenderingException("IO error occurred", e);
+                AsyncMethodPart part = methodNode.getBody().get(i);
+                statementRenderer.setEnd(true);
+                statementRenderer.setCurrentPart(i);
+                part.getStatement().acceptVisitor(statementRenderer);
+                writer.outdent();
             }
+            renderAsyncEpilogue();
+
+            if (methodNode.getModifiers().contains(ElementModifier.SYNCHRONIZED)) {
+                writer.outdent().append("}").ws().append("finally").ws().append('{').indent().softNewLine();
+                writer.append("if").ws().append("(!").appendFunction("$rt_suspending").append("())")
+                        .ws().append("{").indent().softNewLine();
+                writer.appendMethodBody(NameFrequencyEstimator.MONITOR_EXIT_METHOD);
+                writer.append("(");
+                appendMonitor(statementRenderer, methodNode);
+                writer.append(");").softNewLine();
+                writer.outdent().append('}').softNewLine();
+                writer.outdent().append('}').softNewLine();
+            }
+
+            writer.appendFunction("$rt_nativeThread").append("().").append(pushName).append("(");
+            for (int i = firstToSave; i < variableCount; ++i) {
+                writer.append(statementRenderer.variableName(i)).append(',').ws();
+            }
+            writer.append(context.pointerName()).append(");");
+            writer.softNewLine();
         }
 
         @Override
@@ -1155,11 +1117,7 @@ public class Renderer implements RenderingManager {
 
         @Override
         public void typeToClassString(SourceWriter writer, ValueType type) {
-            try {
-                context.typeToClsString(writer, type);
-            } catch (IOException e) {
-                throw new RuntimeException(e);
-            }
+            context.typeToClsString(writer, type);
         }
 
         @Override
@@ -1178,7 +1136,7 @@ public class Renderer implements RenderingManager {
         }
     }
 
-    private void appendMonitor(StatementRenderer statementRenderer, MethodNode methodNode) throws IOException {
+    private void appendMonitor(StatementRenderer statementRenderer, MethodNode methodNode) {
         if (methodNode.getModifiers().contains(ElementModifier.STATIC)) {
             writer.appendFunction("$rt_cls").append("(")
                     .appendClass(methodNode.getReference().getClassName()).append(")");
diff --git a/core/src/main/java/org/teavm/backend/javascript/rendering/RenderingContext.java b/core/src/main/java/org/teavm/backend/javascript/rendering/RenderingContext.java
index f32af0897..e405ffd66 100644
--- a/core/src/main/java/org/teavm/backend/javascript/rendering/RenderingContext.java
+++ b/core/src/main/java/org/teavm/backend/javascript/rendering/RenderingContext.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.backend.javascript.rendering;
 
-import java.io.IOException;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
 import java.util.ArrayDeque;
@@ -222,7 +221,7 @@ public abstract class RenderingContext {
         return readonlyStringPool;
     }
 
-    public void constantToString(SourceWriter writer, Object cst) throws IOException {
+    public void constantToString(SourceWriter writer, Object cst) {
         if (cst == null) {
             writer.append("null");
         }
@@ -297,7 +296,7 @@ public abstract class RenderingContext {
         }
     }
 
-    public void typeToClsString(SourceWriter writer, ValueType type) throws IOException {
+    public void typeToClsString(SourceWriter writer, ValueType type) {
         int arrayCount = 0;
         while (type instanceof ValueType.Array) {
             arrayCount++;
diff --git a/core/src/main/java/org/teavm/backend/javascript/rendering/RenderingUtil.java b/core/src/main/java/org/teavm/backend/javascript/rendering/RenderingUtil.java
index 667ba3a97..5bf3f68cc 100644
--- a/core/src/main/java/org/teavm/backend/javascript/rendering/RenderingUtil.java
+++ b/core/src/main/java/org/teavm/backend/javascript/rendering/RenderingUtil.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.backend.javascript.rendering;
 
-import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
@@ -45,7 +44,7 @@ public final class RenderingUtil {
         return sb.toString();
     }
 
-    public static void writeString(SourceWriter writer, String s) throws IOException {
+    public static void writeString(SourceWriter writer, String s) {
         if (s.isEmpty()) {
             writer.append("\"\"");
             return;
diff --git a/core/src/main/java/org/teavm/backend/javascript/rendering/RuntimeRenderer.java b/core/src/main/java/org/teavm/backend/javascript/rendering/RuntimeRenderer.java
index 2197d4615..16fd1359f 100644
--- a/core/src/main/java/org/teavm/backend/javascript/rendering/RuntimeRenderer.java
+++ b/core/src/main/java/org/teavm/backend/javascript/rendering/RuntimeRenderer.java
@@ -39,15 +39,11 @@ public class RuntimeRenderer {
     }
 
     public void renderRuntime() throws RenderingException {
-        try {
-            renderHandWrittenRuntime("runtime.js");
-            renderHandWrittenRuntime("intern.js");
-        } catch (IOException e) {
-            throw new RenderingException("IO error", e);
-        }
+        renderHandWrittenRuntime("runtime.js");
+        renderHandWrittenRuntime("intern.js");
     }
 
-    public void renderHandWrittenRuntime(String name) throws IOException {
+    public void renderHandWrittenRuntime(String name)  {
         AstRoot ast = parseRuntime(name);
         ast.visit(new StringConstantElimination());
         new TemplatingAstTransformer(classSource).visit(ast);
@@ -56,7 +52,7 @@ public class RuntimeRenderer {
         astWriter.print(ast);
     }
 
-    private AstRoot parseRuntime(String name) throws IOException {
+    private AstRoot parseRuntime(String name) {
         CompilerEnvirons env = new CompilerEnvirons();
         env.setRecoverFromErrors(true);
         env.setLanguageVersion(Context.VERSION_1_8);
@@ -66,6 +62,8 @@ public class RuntimeRenderer {
         try (InputStream input = loader.getResourceAsStream("org/teavm/backend/javascript/" + name);
                 Reader reader = new InputStreamReader(input, StandardCharsets.UTF_8)) {
             return factory.parse(reader, null, 0);
+        } catch (IOException e) {
+            throw new RenderingException(e);
         }
     }
 }
diff --git a/core/src/main/java/org/teavm/backend/javascript/rendering/StatementRenderer.java b/core/src/main/java/org/teavm/backend/javascript/rendering/StatementRenderer.java
index 41739ad6b..35f537fc8 100644
--- a/core/src/main/java/org/teavm/backend/javascript/rendering/StatementRenderer.java
+++ b/core/src/main/java/org/teavm/backend/javascript/rendering/StatementRenderer.java
@@ -17,7 +17,6 @@ package org.teavm.backend.javascript.rendering;
 
 import com.carrotsearch.hppc.IntArrayList;
 import com.carrotsearch.hppc.IntIndexedContainer;
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -146,38 +145,34 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
 
     @Override
     public void visit(AssignmentStatement statement) throws RenderingException {
-        try {
-            debugEmitter.emitStatementStart();
-            if (statement.getLocation() != null) {
-                pushLocation(statement.getLocation());
-            }
-            prevCallSite = debugEmitter.emitCallSite();
-            if (statement.getLeftValue() != null) {
-                if (statement.isAsync()) {
-                    writer.append(context.tempVarName());
-                } else {
-                    precedence = Precedence.COMMA;
-                    statement.getLeftValue().acceptVisitor(this);
-                }
-                writer.ws().append("=").ws();
-            }
-            precedence = Precedence.COMMA;
-            statement.getRightValue().acceptVisitor(this);
-            debugEmitter.emitCallSite();
-            writer.append(";").softNewLine();
+        debugEmitter.emitStatementStart();
+        if (statement.getLocation() != null) {
+            pushLocation(statement.getLocation());
+        }
+        prevCallSite = debugEmitter.emitCallSite();
+        if (statement.getLeftValue() != null) {
             if (statement.isAsync()) {
-                emitSuspendChecker();
-                if (statement.getLeftValue() != null) {
-                    precedence = Precedence.COMMA;
-                    statement.getLeftValue().acceptVisitor(this);
-                    writer.ws().append("=").ws().append(context.tempVarName()).append(";").softNewLine();
-                }
+                writer.append(context.tempVarName());
+            } else {
+                precedence = Precedence.COMMA;
+                statement.getLeftValue().acceptVisitor(this);
             }
-            if (statement.getLocation() != null) {
-                popLocation();
+            writer.ws().append("=").ws();
+        }
+        precedence = Precedence.COMMA;
+        statement.getRightValue().acceptVisitor(this);
+        debugEmitter.emitCallSite();
+        writer.append(";").softNewLine();
+        if (statement.isAsync()) {
+            emitSuspendChecker();
+            if (statement.getLeftValue() != null) {
+                precedence = Precedence.COMMA;
+                statement.getLeftValue().acceptVisitor(this);
+                writer.ws().append("=").ws().append(context.tempVarName()).append(";").softNewLine();
             }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        }
+        if (statement.getLocation() != null) {
+            popLocation();
         }
     }
 
@@ -188,63 +183,59 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
 
     @Override
     public void visit(ConditionalStatement statement) {
-        try {
-            boolean needClosingBracket;
-            while (true) {
-                debugEmitter.emitStatementStart();
-                if (statement.getCondition().getLocation() != null) {
-                    pushLocation(statement.getCondition().getLocation());
+        boolean needClosingBracket;
+        while (true) {
+            debugEmitter.emitStatementStart();
+            if (statement.getCondition().getLocation() != null) {
+                pushLocation(statement.getCondition().getLocation());
+            }
+            prevCallSite = debugEmitter.emitCallSite();
+            writer.append("if").ws().append("(");
+            precedence = Precedence.COMMA;
+            statement.getCondition().acceptVisitor(this);
+            if (statement.getCondition().getLocation() != null) {
+                popLocation();
+            }
+            debugEmitter.emitCallSite();
+            writer.append(")");
+            if (isSimpleIfContent(statement.getConsequent())) {
+                needClosingBracket = false;
+            } else {
+                writer.ws().append("{");
+                needClosingBracket = true;
+            }
+            writer.softNewLine().indent();
+            visitStatements(statement.getConsequent());
+
+            if (!statement.getAlternative().isEmpty()) {
+                writer.outdent();
+                if (needClosingBracket) {
+                    writer.append("}").ws();
                 }
-                prevCallSite = debugEmitter.emitCallSite();
-                writer.append("if").ws().append("(");
-                precedence = Precedence.COMMA;
-                statement.getCondition().acceptVisitor(this);
-                if (statement.getCondition().getLocation() != null) {
-                    popLocation();
+                if (statement.getAlternative().size() == 1
+                        && statement.getAlternative().get(0) instanceof ConditionalStatement) {
+                    statement = (ConditionalStatement) statement.getAlternative().get(0);
+                    writer.append("else ");
+                    continue;
                 }
-                debugEmitter.emitCallSite();
-                writer.append(")");
-                if (isSimpleIfContent(statement.getConsequent())) {
+                writer.append("else");
+                if (isSimpleIfContent(statement.getAlternative())) {
+                    if (minifying) {
+                        writer.append(" ");
+                    }
                     needClosingBracket = false;
                 } else {
                     writer.ws().append("{");
                     needClosingBracket = true;
                 }
-                writer.softNewLine().indent();
-                visitStatements(statement.getConsequent());
-
-                if (!statement.getAlternative().isEmpty()) {
-                    writer.outdent();
-                    if (needClosingBracket) {
-                        writer.append("}").ws();
-                    }
-                    if (statement.getAlternative().size() == 1
-                            && statement.getAlternative().get(0) instanceof ConditionalStatement) {
-                        statement = (ConditionalStatement) statement.getAlternative().get(0);
-                        writer.append("else ");
-                        continue;
-                    }
-                    writer.append("else");
-                    if (isSimpleIfContent(statement.getAlternative())) {
-                        if (minifying) {
-                            writer.append(" ");
-                        }
-                        needClosingBracket = false;
-                    } else {
-                        writer.ws().append("{");
-                        needClosingBracket = true;
-                    }
-                    writer.indent().softNewLine();
-                    visitStatements(statement.getAlternative());
-                }
-                break;
+                writer.indent().softNewLine();
+                visitStatements(statement.getAlternative());
             }
-            writer.outdent();
-            if (needClosingBracket) {
-                writer.append("}").softNewLine();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+            break;
+        }
+        writer.outdent();
+        if (needClosingBracket) {
+            writer.append("}").softNewLine();
         }
     }
 
@@ -259,80 +250,72 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
 
     @Override
     public void visit(SwitchStatement statement) {
-        try {
-            debugEmitter.emitStatementStart();
-            if (statement.getValue().getLocation() != null) {
-                pushLocation(statement.getValue().getLocation());
-            }
-            if (statement.getId() != null) {
-                writer.append(mapBlockId(statement.getId())).append(":").ws();
-            }
-            prevCallSite = debugEmitter.emitCallSite();
-            writer.append("switch").ws().append("(");
-            precedence = Precedence.min();
-            statement.getValue().acceptVisitor(this);
-            if (statement.getValue().getLocation() != null) {
-                popLocation();
-            }
-            debugEmitter.emitCallSite();
-            writer.append(")").ws().append("{").softNewLine().indent();
-            for (SwitchClause clause : statement.getClauses()) {
-                for (int condition : clause.getConditions()) {
-                    writer.append("case ").append(condition).append(":").softNewLine();
-                }
-                writer.indent();
-                boolean oldEnd = end;
-                for (Statement part : clause.getBody()) {
-                    end = false;
-                    part.acceptVisitor(this);
-                }
-                end = oldEnd;
-                writer.outdent();
-            }
-            if (statement.getDefaultClause() != null) {
-                writer.append("default:").softNewLine().indent();
-                boolean oldEnd = end;
-                for (Statement part : statement.getDefaultClause()) {
-                    end = false;
-                    part.acceptVisitor(this);
-                }
-                end = oldEnd;
-                writer.outdent();
-            }
-            writer.outdent().append("}").softNewLine();
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        debugEmitter.emitStatementStart();
+        if (statement.getValue().getLocation() != null) {
+            pushLocation(statement.getValue().getLocation());
         }
-    }
-
-    @Override
-    public void visit(WhileStatement statement) {
-        try {
-            debugEmitter.emitStatementStart();
-            if (statement.getId() != null) {
-                writer.append(mapBlockId(statement.getId())).append(":").ws();
+        if (statement.getId() != null) {
+            writer.append(mapBlockId(statement.getId())).append(":").ws();
+        }
+        prevCallSite = debugEmitter.emitCallSite();
+        writer.append("switch").ws().append("(");
+        precedence = Precedence.min();
+        statement.getValue().acceptVisitor(this);
+        if (statement.getValue().getLocation() != null) {
+            popLocation();
+        }
+        debugEmitter.emitCallSite();
+        writer.append(")").ws().append("{").softNewLine().indent();
+        for (SwitchClause clause : statement.getClauses()) {
+            for (int condition : clause.getConditions()) {
+                writer.append("case ").append(condition).append(":").softNewLine();
             }
-            writer.append("while");
-            writer.ws().append("(");
-            if (statement.getCondition() != null) {
-                prevCallSite = debugEmitter.emitCallSite();
-                precedence = Precedence.min();
-                statement.getCondition().acceptVisitor(this);
-                debugEmitter.emitCallSite();
-            } else {
-                writer.append("true");
-            }
-            writer.append(")").ws().append("{").softNewLine().indent();
+            writer.indent();
             boolean oldEnd = end;
-            for (Statement part : statement.getBody()) {
+            for (Statement part : clause.getBody()) {
                 end = false;
                 part.acceptVisitor(this);
             }
             end = oldEnd;
-            writer.outdent().append("}").softNewLine();
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+            writer.outdent();
         }
+        if (statement.getDefaultClause() != null) {
+            writer.append("default:").softNewLine().indent();
+            boolean oldEnd = end;
+            for (Statement part : statement.getDefaultClause()) {
+                end = false;
+                part.acceptVisitor(this);
+            }
+            end = oldEnd;
+            writer.outdent();
+        }
+        writer.outdent().append("}").softNewLine();
+    }
+
+    @Override
+    public void visit(WhileStatement statement) {
+        debugEmitter.emitStatementStart();
+        if (statement.getId() != null) {
+            writer.append(mapBlockId(statement.getId())).append(":").ws();
+        }
+        writer.append("while");
+        writer.ws().append("(");
+        if (statement.getCondition() != null) {
+            prevCallSite = debugEmitter.emitCallSite();
+            precedence = Precedence.min();
+            statement.getCondition().acceptVisitor(this);
+            debugEmitter.emitCallSite();
+        } else {
+            writer.append("true");
+        }
+        writer.append(")").ws().append("{").softNewLine().indent();
+        boolean oldEnd = end;
+        for (Statement part : statement.getBody()) {
+            end = false;
+            part.acceptVisitor(this);
+        }
+        end = oldEnd;
+        writer.outdent().append("}").softNewLine();
     }
 
     private String mapBlockId(String id) {
@@ -361,97 +344,77 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
 
     @Override
     public void visit(BlockStatement statement) {
-        try {
-            writer.append(mapBlockId(statement.getId())).append(":").ws().append("{").softNewLine().indent();
-            visitStatements(statement.getBody());
-            writer.outdent().append("}").softNewLine();
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
-        }
+        writer.append(mapBlockId(statement.getId())).append(":").ws().append("{").softNewLine().indent();
+        visitStatements(statement.getBody());
+        writer.outdent().append("}").softNewLine();
     }
 
     @Override
     public void visit(BreakStatement statement) {
-        try {
-            debugEmitter.emitStatementStart();
-            if (statement.getLocation() != null) {
-                pushLocation(statement.getLocation());
-            }
-            writer.append("break");
-            if (statement.getTarget() != null) {
-                writer.append(' ').append(mapBlockId(statement.getTarget().getId()));
-            }
-            writer.append(";").softNewLine();
-            if (statement.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        debugEmitter.emitStatementStart();
+        if (statement.getLocation() != null) {
+            pushLocation(statement.getLocation());
+        }
+        writer.append("break");
+        if (statement.getTarget() != null) {
+            writer.append(' ').append(mapBlockId(statement.getTarget().getId()));
+        }
+        writer.append(";").softNewLine();
+        if (statement.getLocation() != null) {
+            popLocation();
         }
     }
 
     @Override
     public void visit(ContinueStatement statement) {
-        try {
-            debugEmitter.emitStatementStart();
-            if (statement.getLocation() != null) {
-                pushLocation(statement.getLocation());
-            }
-            writer.append("continue");
-            if (statement.getTarget() != null) {
-                writer.append(' ').append(mapBlockId(statement.getTarget().getId()));
-            }
-            writer.append(";").softNewLine();
-            if (statement.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        debugEmitter.emitStatementStart();
+        if (statement.getLocation() != null) {
+            pushLocation(statement.getLocation());
+        }
+        writer.append("continue");
+        if (statement.getTarget() != null) {
+            writer.append(' ').append(mapBlockId(statement.getTarget().getId()));
+        }
+        writer.append(";").softNewLine();
+        if (statement.getLocation() != null) {
+            popLocation();
         }
     }
 
     @Override
     public void visit(ReturnStatement statement) {
-        try {
-            debugEmitter.emitStatementStart();
-            if (statement.getLocation() != null) {
-                pushLocation(statement.getLocation());
-            }
-            writer.append("return");
-            if (statement.getResult() != null) {
-                writer.append(' ');
-                prevCallSite = debugEmitter.emitCallSite();
-                precedence = Precedence.min();
-                statement.getResult().acceptVisitor(this);
-                debugEmitter.emitCallSite();
-            }
-            writer.append(";").softNewLine();
-            if (statement.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        debugEmitter.emitStatementStart();
+        if (statement.getLocation() != null) {
+            pushLocation(statement.getLocation());
+        }
+        writer.append("return");
+        if (statement.getResult() != null) {
+            writer.append(' ');
+            prevCallSite = debugEmitter.emitCallSite();
+            precedence = Precedence.min();
+            statement.getResult().acceptVisitor(this);
+            debugEmitter.emitCallSite();
+        }
+        writer.append(";").softNewLine();
+        if (statement.getLocation() != null) {
+            popLocation();
         }
     }
 
     @Override
     public void visit(ThrowStatement statement) {
-        try {
-            debugEmitter.emitStatementStart();
-            if (statement.getLocation() != null) {
-                pushLocation(statement.getLocation());
-            }
-            writer.appendFunction("$rt_throw").append("(");
-            prevCallSite = debugEmitter.emitCallSite();
-            precedence = Precedence.min();
-            statement.getException().acceptVisitor(this);
-            writer.append(");").softNewLine();
-            debugEmitter.emitCallSite();
-            if (statement.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        debugEmitter.emitStatementStart();
+        if (statement.getLocation() != null) {
+            pushLocation(statement.getLocation());
+        }
+        writer.appendFunction("$rt_throw").append("(");
+        prevCallSite = debugEmitter.emitCallSite();
+        precedence = Precedence.min();
+        statement.getException().acceptVisitor(this);
+        writer.append(");").softNewLine();
+        debugEmitter.emitCallSite();
+        if (statement.getLocation() != null) {
+            popLocation();
         }
     }
 
@@ -465,20 +428,16 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
         if (method == null) {
             return;
         }
-        try {
-            debugEmitter.emitStatementStart();
-            if (statement.getLocation() != null) {
-                pushLocation(statement.getLocation());
-            }
-            writer.appendClassInit(statement.getClassName()).append("();").softNewLine();
-            if (statement.isAsync()) {
-                emitSuspendChecker();
-            }
-            if (statement.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        debugEmitter.emitStatementStart();
+        if (statement.getLocation() != null) {
+            pushLocation(statement.getLocation());
+        }
+        writer.appendClassInit(statement.getClassName()).append("();").softNewLine();
+        if (statement.isAsync()) {
+            emitSuspendChecker();
+        }
+        if (statement.getLocation() != null) {
+            popLocation();
         }
     }
 
@@ -492,13 +451,7 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
         }
         if (guarded) {
             visitBinary(BinaryOperation.OR, "|", () -> visitBinary(expr, op, false),
-                    () -> {
-                        try {
-                            writer.append("0");
-                        } catch (IOException e) {
-                            throw new RenderingException("IO error occurred", e);
-                        }
-                    });
+                    () -> writer.append("0"));
         } else {
             visitBinary(expr.getOperation(), op, () -> expr.getFirstOperand().acceptVisitor(this),
                     () -> expr.getSecondOperand().acceptVisitor(this));
@@ -509,56 +462,52 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
     }
 
     private void visitBinary(BinaryOperation operation, String infixText, Runnable a, Runnable b) {
-        try {
-            Precedence outerPrecedence = precedence;
-            Precedence innerPrecedence = getPrecedence(operation);
-            if (innerPrecedence.ordinal() < outerPrecedence.ordinal()) {
-                writer.append('(');
-            }
+        Precedence outerPrecedence = precedence;
+        Precedence innerPrecedence = getPrecedence(operation);
+        if (innerPrecedence.ordinal() < outerPrecedence.ordinal()) {
+            writer.append('(');
+        }
 
-            switch (operation) {
-                case ADD:
-                case SUBTRACT:
-                case MULTIPLY:
-                case DIVIDE:
-                case AND:
-                case OR:
-                case BITWISE_AND:
-                case BITWISE_OR:
-                case BITWISE_XOR:
-                case LEFT_SHIFT:
-                case RIGHT_SHIFT:
-                case UNSIGNED_RIGHT_SHIFT:
-                    precedence = innerPrecedence;
-                    break;
-                default:
-                    precedence = innerPrecedence.next();
-            }
-            a.run();
+        switch (operation) {
+            case ADD:
+            case SUBTRACT:
+            case MULTIPLY:
+            case DIVIDE:
+            case AND:
+            case OR:
+            case BITWISE_AND:
+            case BITWISE_OR:
+            case BITWISE_XOR:
+            case LEFT_SHIFT:
+            case RIGHT_SHIFT:
+            case UNSIGNED_RIGHT_SHIFT:
+                precedence = innerPrecedence;
+                break;
+            default:
+                precedence = innerPrecedence.next();
+        }
+        a.run();
 
-            writer.ws().append(infixText).ws();
+        writer.ws().append(infixText).ws();
 
-            switch (operation) {
-                case ADD:
-                case MULTIPLY:
-                case AND:
-                case OR:
-                case BITWISE_AND:
-                case BITWISE_OR:
-                case BITWISE_XOR:
-                    precedence = innerPrecedence;
-                    break;
-                default:
-                    precedence = innerPrecedence.next();
-                    break;
-            }
-            b.run();
+        switch (operation) {
+            case ADD:
+            case MULTIPLY:
+            case AND:
+            case OR:
+            case BITWISE_AND:
+            case BITWISE_OR:
+            case BITWISE_XOR:
+                precedence = innerPrecedence;
+                break;
+            default:
+                precedence = innerPrecedence.next();
+                break;
+        }
+        b.run();
 
-            if (innerPrecedence.ordinal() < outerPrecedence.ordinal()) {
-                writer.append(')');
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        if (innerPrecedence.ordinal() < outerPrecedence.ordinal()) {
+            writer.append(')');
         }
     }
 
@@ -600,23 +549,19 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
     }
 
     private void visitBinaryFunction(BinaryExpr expr, String function) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
-            }
-            writer.appendFunction(function);
-            writer.append('(');
-            precedence = Precedence.min();
-            expr.getFirstOperand().acceptVisitor(this);
-            writer.append(",").ws();
-            precedence = Precedence.min();
-            expr.getSecondOperand().acceptVisitor(this);
-            writer.append(')');
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
+        writer.appendFunction(function);
+        writer.append('(');
+        precedence = Precedence.min();
+        expr.getFirstOperand().acceptVisitor(this);
+        writer.append(",").ws();
+        precedence = Precedence.min();
+        expr.getSecondOperand().acceptVisitor(this);
+        writer.append(')');
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
@@ -764,140 +709,132 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
 
     @Override
     public void visit(UnaryExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
-            }
-            Precedence outerPrecedence = precedence;
-            switch (expr.getOperation()) {
-                case NOT: {
-                    if (expr.getType() == OperationType.LONG) {
-                        longLibraryUsed = true;
-                        writer.appendFunction("Long_not").append("(");
-                        precedence = Precedence.min();
-                        expr.getOperand().acceptVisitor(this);
-                        writer.append(')');
-                    } else {
-                        if (outerPrecedence.ordinal() > Precedence.UNARY.ordinal()) {
-                            writer.append('(');
-                        }
-                        writer.append(expr.getType() == null ? "!" : "~");
-                        precedence = Precedence.UNARY;
-                        expr.getOperand().acceptVisitor(this);
-                        if (outerPrecedence.ordinal() > Precedence.UNARY.ordinal()) {
-                            writer.append(')');
-                        }
-                    }
-                    break;
-                }
-                case NEGATE:
-                    if (expr.getType() == OperationType.LONG) {
-                        longLibraryUsed = true;
-                        writer.appendFunction("Long_neg").append("(");
-                        precedence = Precedence.min();
-                        expr.getOperand().acceptVisitor(this);
-                        writer.append(')');
-                    } else if (expr.getType() == OperationType.INT) {
-                        if (outerPrecedence.ordinal() > Precedence.BITWISE_OR.ordinal()) {
-                            writer.append('(');
-                        }
-                        writer.append(" -");
-                        precedence = Precedence.UNARY;
-                        expr.getOperand().acceptVisitor(this);
-                        writer.ws().append("|").ws();
-                        writer.append("0");
-                        if (outerPrecedence.ordinal() > Precedence.BITWISE_OR.ordinal()) {
-                            writer.append(')');
-                        }
-                    } else {
-                        if (outerPrecedence.ordinal() > Precedence.UNARY.ordinal()) {
-                            writer.append('(');
-                        }
-                        writer.append(" -");
-                        precedence = Precedence.UNARY;
-                        expr.getOperand().acceptVisitor(this);
-                        if (outerPrecedence.ordinal() > Precedence.UNARY.ordinal()) {
-                            writer.append(')');
-                        }
-                    }
-                    break;
-                case LENGTH:
-                    precedence = Precedence.MEMBER_ACCESS;
-                    expr.getOperand().acceptVisitor(this);
-                    writer.append(".length");
-                    break;
-                case INT_TO_BYTE:
-                    if (outerPrecedence.ordinal() > Precedence.BITWISE_SHIFT.ordinal()) {
-                        writer.append('(');
-                    }
-                    precedence = Precedence.BITWISE_SHIFT;
-                    expr.getOperand().acceptVisitor(this);
-                    writer.ws().append("<<").ws().append("24").ws().append(">>").ws().append("24");
-                    if (outerPrecedence.ordinal() > Precedence.BITWISE_SHIFT.ordinal()) {
-                        writer.append(')');
-                    }
-                    break;
-                case INT_TO_SHORT:
-                    if (outerPrecedence.ordinal() > Precedence.BITWISE_SHIFT.ordinal()) {
-                        writer.append('(');
-                    }
-                    precedence = Precedence.BITWISE_SHIFT;
-                    expr.getOperand().acceptVisitor(this);
-                    writer.ws().append("<<").ws().append("16").ws().append(">>").ws().append("16");
-                    if (outerPrecedence.ordinal() > Precedence.BITWISE_SHIFT.ordinal()) {
-                        writer.append(')');
-                    }
-                    break;
-                case INT_TO_CHAR:
-                    if (outerPrecedence.ordinal() > Precedence.BITWISE_AND.ordinal()) {
-                        writer.append('(');
-                    }
-                    precedence = Precedence.BITWISE_AND;
-                    expr.getOperand().acceptVisitor(this);
-                    writer.ws().append("&").ws().append("65535");
-                    if (outerPrecedence.ordinal() > Precedence.BITWISE_AND.ordinal()) {
-                        writer.append(')');
-                    }
-                    break;
-                case NULL_CHECK:
-                    writer.appendFunction("$rt_nullCheck").append("(");
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
+        Precedence outerPrecedence = precedence;
+        switch (expr.getOperation()) {
+            case NOT: {
+                if (expr.getType() == OperationType.LONG) {
+                    longLibraryUsed = true;
+                    writer.appendFunction("Long_not").append("(");
                     precedence = Precedence.min();
                     expr.getOperand().acceptVisitor(this);
                     writer.append(')');
-                    break;
+                } else {
+                    if (outerPrecedence.ordinal() > Precedence.UNARY.ordinal()) {
+                        writer.append('(');
+                    }
+                    writer.append(expr.getType() == null ? "!" : "~");
+                    precedence = Precedence.UNARY;
+                    expr.getOperand().acceptVisitor(this);
+                    if (outerPrecedence.ordinal() > Precedence.UNARY.ordinal()) {
+                        writer.append(')');
+                    }
+                }
+                break;
             }
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+            case NEGATE:
+                if (expr.getType() == OperationType.LONG) {
+                    longLibraryUsed = true;
+                    writer.appendFunction("Long_neg").append("(");
+                    precedence = Precedence.min();
+                    expr.getOperand().acceptVisitor(this);
+                    writer.append(')');
+                } else if (expr.getType() == OperationType.INT) {
+                    if (outerPrecedence.ordinal() > Precedence.BITWISE_OR.ordinal()) {
+                        writer.append('(');
+                    }
+                    writer.append(" -");
+                    precedence = Precedence.UNARY;
+                    expr.getOperand().acceptVisitor(this);
+                    writer.ws().append("|").ws();
+                    writer.append("0");
+                    if (outerPrecedence.ordinal() > Precedence.BITWISE_OR.ordinal()) {
+                        writer.append(')');
+                    }
+                } else {
+                    if (outerPrecedence.ordinal() > Precedence.UNARY.ordinal()) {
+                        writer.append('(');
+                    }
+                    writer.append(" -");
+                    precedence = Precedence.UNARY;
+                    expr.getOperand().acceptVisitor(this);
+                    if (outerPrecedence.ordinal() > Precedence.UNARY.ordinal()) {
+                        writer.append(')');
+                    }
+                }
+                break;
+            case LENGTH:
+                precedence = Precedence.MEMBER_ACCESS;
+                expr.getOperand().acceptVisitor(this);
+                writer.append(".length");
+                break;
+            case INT_TO_BYTE:
+                if (outerPrecedence.ordinal() > Precedence.BITWISE_SHIFT.ordinal()) {
+                    writer.append('(');
+                }
+                precedence = Precedence.BITWISE_SHIFT;
+                expr.getOperand().acceptVisitor(this);
+                writer.ws().append("<<").ws().append("24").ws().append(">>").ws().append("24");
+                if (outerPrecedence.ordinal() > Precedence.BITWISE_SHIFT.ordinal()) {
+                    writer.append(')');
+                }
+                break;
+            case INT_TO_SHORT:
+                if (outerPrecedence.ordinal() > Precedence.BITWISE_SHIFT.ordinal()) {
+                    writer.append('(');
+                }
+                precedence = Precedence.BITWISE_SHIFT;
+                expr.getOperand().acceptVisitor(this);
+                writer.ws().append("<<").ws().append("16").ws().append(">>").ws().append("16");
+                if (outerPrecedence.ordinal() > Precedence.BITWISE_SHIFT.ordinal()) {
+                    writer.append(')');
+                }
+                break;
+            case INT_TO_CHAR:
+                if (outerPrecedence.ordinal() > Precedence.BITWISE_AND.ordinal()) {
+                    writer.append('(');
+                }
+                precedence = Precedence.BITWISE_AND;
+                expr.getOperand().acceptVisitor(this);
+                writer.ws().append("&").ws().append("65535");
+                if (outerPrecedence.ordinal() > Precedence.BITWISE_AND.ordinal()) {
+                    writer.append(')');
+                }
+                break;
+            case NULL_CHECK:
+                writer.appendFunction("$rt_nullCheck").append("(");
+                precedence = Precedence.min();
+                expr.getOperand().acceptVisitor(this);
+                writer.append(')');
+                break;
+        }
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
     @Override
     public void visit(CastExpr expr) {
         if (context.isStrict()) {
-            try {
-                if (expr.getLocation() != null) {
-                    pushLocation(expr.getLocation());
-                }
+            if (expr.getLocation() != null) {
+                pushLocation(expr.getLocation());
+            }
 
-                if (isClass(expr.getTarget(), context.getClassSource())) {
-                    writer.appendFunction("$rt_castToClass");
-                } else {
-                    writer.appendFunction("$rt_castToInterface");
-                }
-                writer.append("(");
-                precedence = Precedence.min();
-                expr.getValue().acceptVisitor(this);
-                writer.append(",").ws();
-                context.typeToClsString(writer, expr.getTarget());
-                writer.append(")");
-                if (expr.getLocation() != null) {
-                    popLocation();
-                }
-            } catch (IOException e) {
-                throw new RenderingException("IO error occurred", e);
+            if (isClass(expr.getTarget(), context.getClassSource())) {
+                writer.appendFunction("$rt_castToClass");
+            } else {
+                writer.appendFunction("$rt_castToInterface");
+            }
+            writer.append("(");
+            precedence = Precedence.min();
+            expr.getValue().acceptVisitor(this);
+            writer.append(",").ws();
+            context.typeToClsString(writer, expr.getTarget());
+            writer.append(")");
+            if (expr.getLocation() != null) {
+                popLocation();
             }
         } else {
             expr.getValue().acceptVisitor(this);
@@ -915,76 +852,66 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
 
     @Override
     public void visit(PrimitiveCastExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
-            }
-            switch (expr.getSource()) {
-                case INT:
-                    if (expr.getTarget() == OperationType.LONG) {
-                        writer.appendFunction("Long_fromInt").append("(");
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
+        switch (expr.getSource()) {
+            case INT:
+                if (expr.getTarget() == OperationType.LONG) {
+                    writer.appendFunction("Long_fromInt").append("(");
+                    precedence = Precedence.min();
+                    expr.getValue().acceptVisitor(this);
+                    writer.append(')');
+                } else {
+                    expr.getValue().acceptVisitor(this);
+                }
+                break;
+            case LONG:
+                switch (expr.getTarget()) {
+                    case INT:
+                        precedence = Precedence.MEMBER_ACCESS;
+                        Expr longShifted = extractLongRightShiftedBy32(expr.getValue());
+                        if (longShifted != null) {
+                            writer.appendFunction("Long_hi").append("(");
+                            longShifted.acceptVisitor(this);
+                            writer.append(")");
+                        } else {
+                            writer.appendFunction("Long_lo").append("(");
+                            expr.getValue().acceptVisitor(this);
+                            writer.append(")");
+                        }
+                        break;
+                    case FLOAT:
+                    case DOUBLE:
+                        writer.appendFunction("Long_toNumber").append("(");
                         precedence = Precedence.min();
                         expr.getValue().acceptVisitor(this);
                         writer.append(')');
-                    } else {
+                        break;
+                    default:
                         expr.getValue().acceptVisitor(this);
-                    }
-                    break;
-                case LONG:
-                    switch (expr.getTarget()) {
-                        case INT:
-                            precedence = Precedence.MEMBER_ACCESS;
-                            Expr longShifted = extractLongRightShiftedBy32(expr.getValue());
-                            if (longShifted != null) {
-                                writer.appendFunction("Long_hi").append("(");
-                                longShifted.acceptVisitor(this);
-                                writer.append(")");
-                            } else {
-                                writer.appendFunction("Long_lo").append("(");
-                                expr.getValue().acceptVisitor(this);
-                                writer.append(")");
-                            }
-                            break;
-                        case FLOAT:
-                        case DOUBLE:
-                            writer.appendFunction("Long_toNumber").append("(");
-                            precedence = Precedence.min();
-                            expr.getValue().acceptVisitor(this);
-                            writer.append(')');
-                            break;
-                        default:
-                            expr.getValue().acceptVisitor(this);
-                    }
-                    break;
-                case FLOAT:
-                case DOUBLE:
-                    switch (expr.getTarget()) {
-                        case LONG:
-                            writer.appendFunction("Long_fromNumber").append("(");
-                            precedence = Precedence.min();
-                            expr.getValue().acceptVisitor(this);
-                            writer.append(')');
-                            break;
-                        case INT:
-                            visitBinary(BinaryOperation.BITWISE_OR, "|", () -> expr.getValue().acceptVisitor(this),
-                                    () -> {
-                                        try {
-                                            writer.append("0");
-                                        } catch (IOException e) {
-                                            throw new RenderingException("IO error occurred", e);
-                                        }
-                                    });
-                            break;
-                        default:
-                            expr.getValue().acceptVisitor(this);
-                    }
-                    break;
-            }
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+                }
+                break;
+            case FLOAT:
+            case DOUBLE:
+                switch (expr.getTarget()) {
+                    case LONG:
+                        writer.appendFunction("Long_fromNumber").append("(");
+                        precedence = Precedence.min();
+                        expr.getValue().acceptVisitor(this);
+                        writer.append(')');
+                        break;
+                    case INT:
+                        visitBinary(BinaryOperation.BITWISE_OR, "|", () -> expr.getValue().acceptVisitor(this),
+                                () -> writer.append("0"));
+                        break;
+                    default:
+                        expr.getValue().acceptVisitor(this);
+                }
+                break;
+        }
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
@@ -1015,381 +942,341 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
 
     @Override
     public void visit(ConditionalExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
-            }
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
 
-            Precedence outerPrecedence = precedence;
-            if (outerPrecedence.ordinal() > Precedence.CONDITIONAL.ordinal()) {
-                writer.append('(');
-            }
+        Precedence outerPrecedence = precedence;
+        if (outerPrecedence.ordinal() > Precedence.CONDITIONAL.ordinal()) {
+            writer.append('(');
+        }
 
-            precedence = Precedence.CONDITIONAL.next();
-            expr.getCondition().acceptVisitor(this);
-            writer.ws().append("?").ws();
-            precedence = Precedence.CONDITIONAL.next();
-            expr.getConsequent().acceptVisitor(this);
-            writer.ws().append(":").ws();
-            precedence = Precedence.CONDITIONAL;
-            expr.getAlternative().acceptVisitor(this);
+        precedence = Precedence.CONDITIONAL.next();
+        expr.getCondition().acceptVisitor(this);
+        writer.ws().append("?").ws();
+        precedence = Precedence.CONDITIONAL.next();
+        expr.getConsequent().acceptVisitor(this);
+        writer.ws().append(":").ws();
+        precedence = Precedence.CONDITIONAL;
+        expr.getAlternative().acceptVisitor(this);
 
-            if (outerPrecedence.ordinal() > Precedence.CONDITIONAL.ordinal()) {
-                writer.append(')');
-            }
+        if (outerPrecedence.ordinal() > Precedence.CONDITIONAL.ordinal()) {
+            writer.append(')');
+        }
 
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
     @Override
     public void visit(ConstantExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
-            }
-            context.constantToString(writer, expr.getValue());
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
+        context.constantToString(writer, expr.getValue());
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
     @Override
     public void visit(VariableExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
-            }
-            writer.append(variableName(expr.getIndex()));
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
+        writer.append(variableName(expr.getIndex()));
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
     @Override
     public void visit(SubscriptExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
-            }
-            precedence = Precedence.MEMBER_ACCESS;
-            expr.getArray().acceptVisitor(this);
-            writer.append('[');
-            precedence = Precedence.min();
-            expr.getIndex().acceptVisitor(this);
-            writer.append(']');
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
+        precedence = Precedence.MEMBER_ACCESS;
+        expr.getArray().acceptVisitor(this);
+        writer.append('[');
+        precedence = Precedence.min();
+        expr.getIndex().acceptVisitor(this);
+        writer.append(']');
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
     @Override
     public void visit(UnwrapArrayExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
-            }
-            precedence = Precedence.MEMBER_ACCESS;
-            expr.getArray().acceptVisitor(this);
-            writer.append(".data");
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
+        precedence = Precedence.MEMBER_ACCESS;
+        expr.getArray().acceptVisitor(this);
+        writer.append(".data");
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
     @Override
     public void visit(InvocationExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
+        Injector injector = context.getInjector(expr.getMethod());
+        if (injector != null) {
+            injector.generate(new InjectorContextImpl(expr.getArguments()), expr.getMethod());
+        } else {
+            Precedence outerPrecedence = precedence;
+            if (outerPrecedence.ordinal() > Precedence.FUNCTION_CALL.ordinal()) {
+                writer.append('(');
             }
-            Injector injector = context.getInjector(expr.getMethod());
-            if (injector != null) {
-                injector.generate(new InjectorContextImpl(expr.getArguments()), expr.getMethod());
-            } else {
-                Precedence outerPrecedence = precedence;
-                if (outerPrecedence.ordinal() > Precedence.FUNCTION_CALL.ordinal()) {
-                    writer.append('(');
-                }
 
-                if (expr.getType() == InvocationType.DYNAMIC) {
-                    precedence = Precedence.MEMBER_ACCESS;
-                    expr.getArguments().get(0).acceptVisitor(this);
-                }
-                MethodReference method = expr.getMethod();
-                String name = naming.getNameFor(method.getDescriptor());
-                DeferredCallSite callSite = prevCallSite;
-                boolean shouldEraseCallSite = lastCallSite == null;
-                if (lastCallSite == null) {
-                    lastCallSite = callSite;
-                }
-                boolean virtual = false;
-                switch (expr.getType()) {
-                    case STATIC:
-                        writer.appendMethodBody(method).append("(");
-                        prevCallSite = debugEmitter.emitCallSite();
-                        for (int i = 0; i < expr.getArguments().size(); ++i) {
-                            if (i > 0) {
-                                writer.append(",").ws();
-                            }
-                            precedence = Precedence.min();
-                            expr.getArguments().get(i).acceptVisitor(this);
-                        }
-                        break;
-                    case SPECIAL:
-                        writer.appendMethodBody(method).append("(");
-                        prevCallSite = debugEmitter.emitCallSite();
-                        precedence = Precedence.min();
-                        expr.getArguments().get(0).acceptVisitor(this);
-                        for (int i = 1; i < expr.getArguments().size(); ++i) {
+            if (expr.getType() == InvocationType.DYNAMIC) {
+                precedence = Precedence.MEMBER_ACCESS;
+                expr.getArguments().get(0).acceptVisitor(this);
+            }
+            MethodReference method = expr.getMethod();
+            String name = naming.getNameFor(method.getDescriptor());
+            DeferredCallSite callSite = prevCallSite;
+            boolean shouldEraseCallSite = lastCallSite == null;
+            if (lastCallSite == null) {
+                lastCallSite = callSite;
+            }
+            boolean virtual = false;
+            switch (expr.getType()) {
+                case STATIC:
+                    writer.appendMethodBody(method).append("(");
+                    prevCallSite = debugEmitter.emitCallSite();
+                    for (int i = 0; i < expr.getArguments().size(); ++i) {
+                        if (i > 0) {
                             writer.append(",").ws();
-                            precedence = Precedence.min();
-                            expr.getArguments().get(i).acceptVisitor(this);
                         }
-                        break;
-                    case DYNAMIC:
-                        writer.append(".").append(name).append("(");
-                        prevCallSite = debugEmitter.emitCallSite();
-                        for (int i = 1; i < expr.getArguments().size(); ++i) {
-                            if (i > 1) {
-                                writer.append(",").ws();
-                            }
-                            precedence = Precedence.min();
-                            expr.getArguments().get(i).acceptVisitor(this);
-                        }
-                        virtual = true;
-                        break;
-                    case CONSTRUCTOR:
-                        writer.appendInit(expr.getMethod()).append("(");
-                        prevCallSite = debugEmitter.emitCallSite();
-                        for (int i = 0; i < expr.getArguments().size(); ++i) {
-                            if (i > 0) {
-                                writer.append(",").ws();
-                            }
-                            precedence = Precedence.min();
-                            expr.getArguments().get(i).acceptVisitor(this);
-                        }
-                        break;
-                }
-                writer.append(')');
-                if (lastCallSite != null) {
-                    if (virtual) {
-                        lastCallSite.setVirtualMethod(expr.getMethod());
-                    } else {
-                        lastCallSite.setStaticMethod(expr.getMethod());
+                        precedence = Precedence.min();
+                        expr.getArguments().get(i).acceptVisitor(this);
                     }
-                    lastCallSite = callSite;
-                }
-                if (shouldEraseCallSite) {
-                    lastCallSite = null;
+                    break;
+                case SPECIAL:
+                    writer.appendMethodBody(method).append("(");
+                    prevCallSite = debugEmitter.emitCallSite();
+                    precedence = Precedence.min();
+                    expr.getArguments().get(0).acceptVisitor(this);
+                    for (int i = 1; i < expr.getArguments().size(); ++i) {
+                        writer.append(",").ws();
+                        precedence = Precedence.min();
+                        expr.getArguments().get(i).acceptVisitor(this);
+                    }
+                    break;
+                case DYNAMIC:
+                    writer.append(".").append(name).append("(");
+                    prevCallSite = debugEmitter.emitCallSite();
+                    for (int i = 1; i < expr.getArguments().size(); ++i) {
+                        if (i > 1) {
+                            writer.append(",").ws();
+                        }
+                        precedence = Precedence.min();
+                        expr.getArguments().get(i).acceptVisitor(this);
+                    }
+                    virtual = true;
+                    break;
+                case CONSTRUCTOR:
+                    writer.appendInit(expr.getMethod()).append("(");
+                    prevCallSite = debugEmitter.emitCallSite();
+                    for (int i = 0; i < expr.getArguments().size(); ++i) {
+                        if (i > 0) {
+                            writer.append(",").ws();
+                        }
+                        precedence = Precedence.min();
+                        expr.getArguments().get(i).acceptVisitor(this);
+                    }
+                    break;
+            }
+            writer.append(')');
+            if (lastCallSite != null) {
+                if (virtual) {
+                    lastCallSite.setVirtualMethod(expr.getMethod());
+                } else {
+                    lastCallSite.setStaticMethod(expr.getMethod());
                 }
+                lastCallSite = callSite;
+            }
+            if (shouldEraseCallSite) {
+                lastCallSite = null;
+            }
 
-                if (outerPrecedence.ordinal() > Precedence.FUNCTION_CALL.ordinal()) {
-                    writer.append(')');
-                }
+            if (outerPrecedence.ordinal() > Precedence.FUNCTION_CALL.ordinal()) {
+                writer.append(')');
             }
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        }
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
     @Override
     public void visit(QualificationExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
-            }
-            precedence = Precedence.MEMBER_ACCESS;
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
+        precedence = Precedence.MEMBER_ACCESS;
 
-            if (expr.getQualified() != null) {
-                expr.getQualified().acceptVisitor(this);
-                writer.append('.').appendField(expr.getField());
-            } else {
-                writer.appendStaticField(expr.getField());
-            }
+        if (expr.getQualified() != null) {
+            expr.getQualified().acceptVisitor(this);
+            writer.append('.').appendField(expr.getField());
+        } else {
+            writer.appendStaticField(expr.getField());
+        }
 
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
     @Override
     public void visit(NewExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
-            }
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
 
-            Precedence outerPrecedence = precedence;
-            if (outerPrecedence.ordinal() > Precedence.NEW.ordinal()) {
-                writer.append('(');
-            }
+        Precedence outerPrecedence = precedence;
+        if (outerPrecedence.ordinal() > Precedence.NEW.ordinal()) {
+            writer.append('(');
+        }
 
-            precedence = Precedence.NEW;
+        precedence = Precedence.NEW;
 
-            writer.append("new ").appendClass(expr.getConstructedClass());
-            if (outerPrecedence.ordinal() > Precedence.NEW.ordinal()) {
-                writer.append(')');
-            }
+        writer.append("new ").appendClass(expr.getConstructedClass());
+        if (outerPrecedence.ordinal() > Precedence.NEW.ordinal()) {
+            writer.append(')');
+        }
 
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
     @Override
     public void visit(NewArrayExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
+        ValueType type = expr.getType();
+        if (type instanceof ValueType.Primitive) {
+            switch (((ValueType.Primitive) type).getKind()) {
+                case BOOLEAN:
+                    writer.appendFunction("$rt_createBooleanArray").append("(");
+                    precedence = Precedence.min();
+                    expr.getLength().acceptVisitor(this);
+                    writer.append(")");
+                    break;
+                case BYTE:
+                    writer.appendFunction("$rt_createByteArray").append("(");
+                    precedence = Precedence.min();
+                    expr.getLength().acceptVisitor(this);
+                    writer.append(")");
+                    break;
+                case SHORT:
+                    writer.appendFunction("$rt_createShortArray").append("(");
+                    precedence = Precedence.min();
+                    expr.getLength().acceptVisitor(this);
+                    writer.append(")");
+                    break;
+                case INTEGER:
+                    writer.appendFunction("$rt_createIntArray").append("(");
+                    precedence = Precedence.min();
+                    expr.getLength().acceptVisitor(this);
+                    writer.append(")");
+                    break;
+                case LONG:
+                    writer.appendFunction("$rt_createLongArray").append("(");
+                    precedence = Precedence.min();
+                    expr.getLength().acceptVisitor(this);
+                    writer.append(")");
+                    break;
+                case FLOAT:
+                    writer.appendFunction("$rt_createFloatArray").append("(");
+                    precedence = Precedence.min();
+                    expr.getLength().acceptVisitor(this);
+                    writer.append(")");
+                    break;
+                case DOUBLE:
+                    writer.appendFunction("$rt_createDoubleArray").append("(");
+                    precedence = Precedence.min();
+                    expr.getLength().acceptVisitor(this);
+                    writer.append(")");
+                    break;
+                case CHARACTER:
+                    writer.appendFunction("$rt_createCharArray").append("(");
+                    precedence = Precedence.min();
+                    expr.getLength().acceptVisitor(this);
+                    writer.append(")");
+                    break;
             }
-            ValueType type = expr.getType();
-            if (type instanceof ValueType.Primitive) {
-                switch (((ValueType.Primitive) type).getKind()) {
-                    case BOOLEAN:
-                        writer.appendFunction("$rt_createBooleanArray").append("(");
-                        precedence = Precedence.min();
-                        expr.getLength().acceptVisitor(this);
-                        writer.append(")");
-                        break;
-                    case BYTE:
-                        writer.appendFunction("$rt_createByteArray").append("(");
-                        precedence = Precedence.min();
-                        expr.getLength().acceptVisitor(this);
-                        writer.append(")");
-                        break;
-                    case SHORT:
-                        writer.appendFunction("$rt_createShortArray").append("(");
-                        precedence = Precedence.min();
-                        expr.getLength().acceptVisitor(this);
-                        writer.append(")");
-                        break;
-                    case INTEGER:
-                        writer.appendFunction("$rt_createIntArray").append("(");
-                        precedence = Precedence.min();
-                        expr.getLength().acceptVisitor(this);
-                        writer.append(")");
-                        break;
-                    case LONG:
-                        writer.appendFunction("$rt_createLongArray").append("(");
-                        precedence = Precedence.min();
-                        expr.getLength().acceptVisitor(this);
-                        writer.append(")");
-                        break;
-                    case FLOAT:
-                        writer.appendFunction("$rt_createFloatArray").append("(");
-                        precedence = Precedence.min();
-                        expr.getLength().acceptVisitor(this);
-                        writer.append(")");
-                        break;
-                    case DOUBLE:
-                        writer.appendFunction("$rt_createDoubleArray").append("(");
-                        precedence = Precedence.min();
-                        expr.getLength().acceptVisitor(this);
-                        writer.append(")");
-                        break;
-                    case CHARACTER:
-                        writer.appendFunction("$rt_createCharArray").append("(");
-                        precedence = Precedence.min();
-                        expr.getLength().acceptVisitor(this);
-                        writer.append(")");
-                        break;
-                }
-            } else {
-                writer.appendFunction("$rt_createArray").append("(");
-                context.typeToClsString(writer, expr.getType());
-                writer.append(",").ws();
-                precedence = Precedence.min();
-                expr.getLength().acceptVisitor(this);
-                writer.append(")");
-            }
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        } else {
+            writer.appendFunction("$rt_createArray").append("(");
+            context.typeToClsString(writer, expr.getType());
+            writer.append(",").ws();
+            precedence = Precedence.min();
+            expr.getLength().acceptVisitor(this);
+            writer.append(")");
+        }
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
     @Override
     public void visit(ArrayFromDataExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
-            }
-            ValueType type = expr.getType();
-            if (type instanceof ValueType.Primitive) {
-                switch (((ValueType.Primitive) type).getKind()) {
-                    case BOOLEAN:
-                        writer.appendFunction("$rt_createBooleanArrayFromData");
-                        break;
-                    case BYTE:
-                        writer.appendFunction("$rt_createByteArrayFromData");
-                        break;
-                    case SHORT:
-                        writer.appendFunction("$rt_createShortArrayFromData");
-                        break;
-                    case INTEGER:
-                        writer.appendFunction("$rt_createIntArrayFromData");
-                        break;
-                    case LONG:
-                        writer.appendFunction("$rt_createLongArrayFromData");
-                        break;
-                    case FLOAT:
-                        writer.appendFunction("$rt_createFloatArrayFromData");
-                        break;
-                    case DOUBLE:
-                        writer.appendFunction("$rt_createDoubleArrayFromData");
-                        break;
-                    case CHARACTER:
-                        writer.appendFunction("$rt_createCharArrayFromData");
-                        break;
-                }
-                writer.append("(");
-            } else {
-                writer.appendFunction("$rt_createArrayFromData").append("(");
-                context.typeToClsString(writer, expr.getType());
-                writer.append(",").ws();
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
+        ValueType type = expr.getType();
+        if (type instanceof ValueType.Primitive) {
+            switch (((ValueType.Primitive) type).getKind()) {
+                case BOOLEAN:
+                    writer.appendFunction("$rt_createBooleanArrayFromData");
+                    break;
+                case BYTE:
+                    writer.appendFunction("$rt_createByteArrayFromData");
+                    break;
+                case SHORT:
+                    writer.appendFunction("$rt_createShortArrayFromData");
+                    break;
+                case INTEGER:
+                    writer.appendFunction("$rt_createIntArrayFromData");
+                    break;
+                case LONG:
+                    writer.appendFunction("$rt_createLongArrayFromData");
+                    break;
+                case FLOAT:
+                    writer.appendFunction("$rt_createFloatArrayFromData");
+                    break;
+                case DOUBLE:
+                    writer.appendFunction("$rt_createDoubleArrayFromData");
+                    break;
+                case CHARACTER:
+                    writer.appendFunction("$rt_createCharArrayFromData");
+                    break;
             }
+            writer.append("(");
+        } else {
+            writer.appendFunction("$rt_createArrayFromData").append("(");
+            context.typeToClsString(writer, expr.getType());
+            writer.append(",").ws();
+        }
 
-            writer.append("[");
-            writeCommaSeparated(expr.getData());
-            writer.append("])");
+        writer.append("[");
+        writeCommaSeparated(expr.getData());
+        writer.append("])");
 
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
-    private void writeCommaSeparated(List<Expr> expressions) throws IOException {
+    private void writeCommaSeparated(List<Expr> expressions) {
         boolean first = true;
         for (Expr element : expressions) {
             if (!first) {
@@ -1403,98 +1290,90 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
 
     @Override
     public void visit(NewMultiArrayExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
+        ValueType type = expr.getType();
+        for (int i = 0; i < expr.getDimensions().size(); ++i) {
+            type = ((ValueType.Array) type).getItemType();
+        }
+        if (type instanceof ValueType.Primitive) {
+            switch (((ValueType.Primitive) type).getKind()) {
+                case BOOLEAN:
+                    writer.appendFunction("$rt_createBooleanMultiArray").append("(");
+                    break;
+                case BYTE:
+                    writer.appendFunction("$rt_createByteMultiArray").append("(");
+                    break;
+                case SHORT:
+                    writer.appendFunction("$rt_createShortMultiArray").append("(");
+                    break;
+                case INTEGER:
+                    writer.appendFunction("$rt_createIntMultiArray").append("(");
+                    break;
+                case LONG:
+                    writer.appendFunction("$rt_createLongMultiArray").append("(");
+                    break;
+                case FLOAT:
+                    writer.appendFunction("$rt_createFloatMultiArray").append("(");
+                    break;
+                case DOUBLE:
+                    writer.appendFunction("$rt_createDoubleMultiArray").append("(");
+                    break;
+                case CHARACTER:
+                    writer.appendFunction("$rt_createCharMultiArray").append("(");
+                    break;
             }
-            ValueType type = expr.getType();
-            for (int i = 0; i < expr.getDimensions().size(); ++i) {
-                type = ((ValueType.Array) type).getItemType();
-            }
-            if (type instanceof ValueType.Primitive) {
-                switch (((ValueType.Primitive) type).getKind()) {
-                    case BOOLEAN:
-                        writer.appendFunction("$rt_createBooleanMultiArray").append("(");
-                        break;
-                    case BYTE:
-                        writer.appendFunction("$rt_createByteMultiArray").append("(");
-                        break;
-                    case SHORT:
-                        writer.appendFunction("$rt_createShortMultiArray").append("(");
-                        break;
-                    case INTEGER:
-                        writer.appendFunction("$rt_createIntMultiArray").append("(");
-                        break;
-                    case LONG:
-                        writer.appendFunction("$rt_createLongMultiArray").append("(");
-                        break;
-                    case FLOAT:
-                        writer.appendFunction("$rt_createFloatMultiArray").append("(");
-                        break;
-                    case DOUBLE:
-                        writer.appendFunction("$rt_createDoubleMultiArray").append("(");
-                        break;
-                    case CHARACTER:
-                        writer.appendFunction("$rt_createCharMultiArray").append("(");
-                        break;
-                }
-            } else {
-                writer.appendFunction("$rt_createMultiArray").append("(");
-                context.typeToClsString(writer, type);
+        } else {
+            writer.appendFunction("$rt_createMultiArray").append("(");
+            context.typeToClsString(writer, type);
+            writer.append(",").ws();
+        }
+        writer.append("[");
+        boolean first = true;
+        List<Expr> dimensions = new ArrayList<>(expr.getDimensions());
+        Collections.reverse(dimensions);
+        for (Expr dimension : dimensions) {
+            if (!first) {
                 writer.append(",").ws();
             }
-            writer.append("[");
-            boolean first = true;
-            List<Expr> dimensions = new ArrayList<>(expr.getDimensions());
-            Collections.reverse(dimensions);
-            for (Expr dimension : dimensions) {
-                if (!first) {
-                    writer.append(",").ws();
-                }
-                first = false;
-                precedence = Precedence.min();
-                dimension.acceptVisitor(this);
-            }
-            writer.append("])");
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+            first = false;
+            precedence = Precedence.min();
+            dimension.acceptVisitor(this);
+        }
+        writer.append("])");
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
     @Override
     public void visit(InstanceOfExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
+        if (isClass(expr.getType(), context.getClassSource())) {
+            boolean needsParentheses = Precedence.COMPARISON.ordinal() < precedence.ordinal();
+            if (needsParentheses) {
+                writer.append('(');
             }
-            if (isClass(expr.getType(), context.getClassSource())) {
-                boolean needsParentheses = Precedence.COMPARISON.ordinal() < precedence.ordinal();
-                if (needsParentheses) {
-                    writer.append('(');
-                }
-                precedence = Precedence.CONDITIONAL.next();
-                expr.getExpr().acceptVisitor(this);
-                writer.append(" instanceof ");
-                context.typeToClsString(writer, expr.getType());
-                if (needsParentheses) {
-                    writer.append(')');
-                }
-            } else {
-                writer.appendFunction("$rt_isInstance").append("(");
-                precedence = Precedence.min();
-                expr.getExpr().acceptVisitor(this);
-                writer.append(",").ws();
-                context.typeToClsString(writer, expr.getType());
-                writer.append(")");
+            precedence = Precedence.CONDITIONAL.next();
+            expr.getExpr().acceptVisitor(this);
+            writer.append(" instanceof ");
+            context.typeToClsString(writer, expr.getType());
+            if (needsParentheses) {
+                writer.append(')');
             }
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        } else {
+            writer.appendFunction("$rt_isInstance").append("(");
+            precedence = Precedence.min();
+            expr.getExpr().acceptVisitor(this);
+            writer.append(",").ws();
+            context.typeToClsString(writer, expr.getType());
+            writer.append(")");
+        }
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
@@ -1514,107 +1393,95 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
 
     @Override
     public void visit(TryCatchStatement statement) {
-        try {
-            writer.append("try").ws().append("{").softNewLine().indent();
-            List<TryCatchStatement> sequence = new ArrayList<>();
-            sequence.add(statement);
-            List<Statement> protectedBody = statement.getProtectedBody();
-            while (protectedBody.size() == 1 && protectedBody.get(0) instanceof TryCatchStatement) {
-                TryCatchStatement nextStatement = (TryCatchStatement) protectedBody.get(0);
-                sequence.add(nextStatement);
-                protectedBody = nextStatement.getProtectedBody();
-            }
-            visitStatements(protectedBody);
-            writer.outdent().append("}").ws().append("catch").ws().append("($$e)")
-                    .ws().append("{").indent().softNewLine();
-            writer.append("$$je").ws().append("=").ws().appendFunction("$rt_wrapException").append("($$e);")
-                    .softNewLine();
-            boolean first = true;
-            boolean defaultHandlerOccurred = false;
-            for (int i = sequence.size() - 1; i >= 0; --i) {
-                TryCatchStatement catchClause = sequence.get(i);
-                if (!first) {
-                    writer.ws().append("else");
-                }
-                if (catchClause.getExceptionType() != null) {
-                    if (!first) {
-                        writer.append(" ");
-                    }
-                    writer.append("if").ws().append("($$je instanceof ").appendClass(catchClause.getExceptionType());
-                    writer.append(")").ws();
-                } else {
-                    defaultHandlerOccurred = true;
-                }
-
-                if (catchClause.getExceptionType() != null || !first) {
-                    writer.append("{").indent().softNewLine();
-                }
-
-                if (catchClause.getExceptionVariable() != null) {
-                    writer.append(variableName(catchClause.getExceptionVariable())).ws().append("=").ws()
-                            .append("$$je;").softNewLine();
-                }
-                visitStatements(catchClause.getHandler());
-
-                if (catchClause.getExceptionType() != null || !first) {
-                    writer.outdent().append("}");
-                }
-
-                first = false;
-
-                if (defaultHandlerOccurred) {
-                    break;
-                }
-            }
-            if (!defaultHandlerOccurred) {
-                writer.ws().append("else").ws().append("{").indent().softNewLine();
-                writer.append("throw $$e;").softNewLine();
-                writer.outdent().append("}").softNewLine();
-            } else {
-                writer.softNewLine();
-            }
-            writer.outdent().append("}").softNewLine();
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        writer.append("try").ws().append("{").softNewLine().indent();
+        List<TryCatchStatement> sequence = new ArrayList<>();
+        sequence.add(statement);
+        List<Statement> protectedBody = statement.getProtectedBody();
+        while (protectedBody.size() == 1 && protectedBody.get(0) instanceof TryCatchStatement) {
+            TryCatchStatement nextStatement = (TryCatchStatement) protectedBody.get(0);
+            sequence.add(nextStatement);
+            protectedBody = nextStatement.getProtectedBody();
         }
+        visitStatements(protectedBody);
+        writer.outdent().append("}").ws().append("catch").ws().append("($$e)")
+                .ws().append("{").indent().softNewLine();
+        writer.append("$$je").ws().append("=").ws().appendFunction("$rt_wrapException").append("($$e);")
+                .softNewLine();
+        boolean first = true;
+        boolean defaultHandlerOccurred = false;
+        for (int i = sequence.size() - 1; i >= 0; --i) {
+            TryCatchStatement catchClause = sequence.get(i);
+            if (!first) {
+                writer.ws().append("else");
+            }
+            if (catchClause.getExceptionType() != null) {
+                if (!first) {
+                    writer.append(" ");
+                }
+                writer.append("if").ws().append("($$je instanceof ").appendClass(catchClause.getExceptionType());
+                writer.append(")").ws();
+            } else {
+                defaultHandlerOccurred = true;
+            }
+
+            if (catchClause.getExceptionType() != null || !first) {
+                writer.append("{").indent().softNewLine();
+            }
+
+            if (catchClause.getExceptionVariable() != null) {
+                writer.append(variableName(catchClause.getExceptionVariable())).ws().append("=").ws()
+                        .append("$$je;").softNewLine();
+            }
+            visitStatements(catchClause.getHandler());
+
+            if (catchClause.getExceptionType() != null || !first) {
+                writer.outdent().append("}");
+            }
+
+            first = false;
+
+            if (defaultHandlerOccurred) {
+                break;
+            }
+        }
+        if (!defaultHandlerOccurred) {
+            writer.ws().append("else").ws().append("{").indent().softNewLine();
+            writer.append("throw $$e;").softNewLine();
+            writer.outdent().append("}").softNewLine();
+        } else {
+            writer.softNewLine();
+        }
+        writer.outdent().append("}").softNewLine();
     }
 
     @Override
     public void visit(GotoPartStatement statement) {
-        try {
-            if (statement.getPart() != currentPart) {
-                writer.append(context.pointerName()).ws().append("=").ws().append(statement.getPart()).append(";")
-                        .softNewLine();
-            }
-            if (!end || statement.getPart() != currentPart + 1) {
-                writer.append("continue ").append(context.mainLoopName()).append(";").softNewLine();
-            }
-        } catch (IOException ex) {
-            throw new RenderingException("IO error occurred", ex);
+        if (statement.getPart() != currentPart) {
+            writer.append(context.pointerName()).ws().append("=").ws().append(statement.getPart()).append(";")
+                    .softNewLine();
+        }
+        if (!end || statement.getPart() != currentPart + 1) {
+            writer.append("continue ").append(context.mainLoopName()).append(";").softNewLine();
         }
     }
 
     @Override
     public void visit(MonitorEnterStatement statement) {
-        try {
-            if (async) {
-                writer.appendMethodBody(NameFrequencyEstimator.MONITOR_ENTER_METHOD).append("(");
-                precedence = Precedence.min();
-                statement.getObjectRef().acceptVisitor(this);
-                writer.append(");").softNewLine();
-                emitSuspendChecker();
-            } else {
-                writer.appendMethodBody(NameFrequencyEstimator.MONITOR_ENTER_SYNC_METHOD).append('(');
-                precedence = Precedence.min();
-                statement.getObjectRef().acceptVisitor(this);
-                writer.append(");").softNewLine();
-            }
-        } catch (IOException ex) {
-            throw new RenderingException("IO error occurred", ex);
+        if (async) {
+            writer.appendMethodBody(NameFrequencyEstimator.MONITOR_ENTER_METHOD).append("(");
+            precedence = Precedence.min();
+            statement.getObjectRef().acceptVisitor(this);
+            writer.append(");").softNewLine();
+            emitSuspendChecker();
+        } else {
+            writer.appendMethodBody(NameFrequencyEstimator.MONITOR_ENTER_SYNC_METHOD).append('(');
+            precedence = Precedence.min();
+            statement.getObjectRef().acceptVisitor(this);
+            writer.append(");").softNewLine();
         }
     }
 
-    public void emitSuspendChecker() throws IOException {
+    public void emitSuspendChecker() {
         writer.append("if").ws().append("(").appendFunction("$rt_suspending").append("())").ws()
                 .append("{").indent().softNewLine();
         writer.append("break ").append(context.mainLoopName()).append(";").softNewLine();
@@ -1623,54 +1490,46 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
 
     @Override
     public void visit(MonitorExitStatement statement) {
-        try {
-            if (async) {
-                writer.appendMethodBody(NameFrequencyEstimator.MONITOR_EXIT_METHOD).append("(");
-                precedence = Precedence.min();
-                statement.getObjectRef().acceptVisitor(this);
-                writer.append(");").softNewLine();
-            } else {
-                writer.appendMethodBody(NameFrequencyEstimator.MONITOR_EXIT_SYNC_METHOD).append('(');
-                precedence = Precedence.min();
-                statement.getObjectRef().acceptVisitor(this);
-                writer.append(");").softNewLine();
-            }
-        } catch (IOException ex) {
-            throw new RenderingException("IO error occurred", ex);
+        if (async) {
+            writer.appendMethodBody(NameFrequencyEstimator.MONITOR_EXIT_METHOD).append("(");
+            precedence = Precedence.min();
+            statement.getObjectRef().acceptVisitor(this);
+            writer.append(");").softNewLine();
+        } else {
+            writer.appendMethodBody(NameFrequencyEstimator.MONITOR_EXIT_SYNC_METHOD).append('(');
+            precedence = Precedence.min();
+            statement.getObjectRef().acceptVisitor(this);
+            writer.append(");").softNewLine();
         }
     }
 
     @Override
     public void visit(BoundCheckExpr expr) {
-        try {
-            if (expr.getLocation() != null) {
-                pushLocation(expr.getLocation());
-            }
+        if (expr.getLocation() != null) {
+            pushLocation(expr.getLocation());
+        }
 
-            if (expr.getArray() != null && expr.isLower()) {
-                writer.appendFunction("$rt_checkBounds").append("(");
-            } else if (expr.getArray() != null) {
-                writer.appendFunction("$rt_checkUpperBound").append("(");
-            } else if (expr.isLower()) {
-                writer.appendFunction("$rt_checkLowerBound").append("(");
-            }
+        if (expr.getArray() != null && expr.isLower()) {
+            writer.appendFunction("$rt_checkBounds").append("(");
+        } else if (expr.getArray() != null) {
+            writer.appendFunction("$rt_checkUpperBound").append("(");
+        } else if (expr.isLower()) {
+            writer.appendFunction("$rt_checkLowerBound").append("(");
+        }
 
-            expr.getIndex().acceptVisitor(this);
+        expr.getIndex().acceptVisitor(this);
 
-            if (expr.getArray() != null) {
-                writer.append(",").ws();
-                expr.getArray().acceptVisitor(this);
-            }
+        if (expr.getArray() != null) {
+            writer.append(",").ws();
+            expr.getArray().acceptVisitor(this);
+        }
 
-            if (expr.getArray() != null || expr.isLower()) {
-                writer.append(")");
-            }
+        if (expr.getArray() != null || expr.isLower()) {
+            writer.append(")");
+        }
 
-            if (expr.getLocation() != null) {
-                popLocation();
-            }
-        } catch (IOException e) {
-            throw new RenderingException("IO error occurred", e);
+        if (expr.getLocation() != null) {
+            popLocation();
         }
     }
 
@@ -1698,12 +1557,12 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
         }
 
         @Override
-        public void writeEscaped(String str) throws IOException {
+        public void writeEscaped(String str) {
             writer.append(RenderingUtil.escapeString(str));
         }
 
         @Override
-        public void writeType(ValueType type) throws IOException {
+        public void writeType(ValueType type) {
             context.typeToClsString(writer, type);
         }
 
diff --git a/core/src/main/java/org/teavm/backend/javascript/spi/Generator.java b/core/src/main/java/org/teavm/backend/javascript/spi/Generator.java
index 138d3797a..235040260 100644
--- a/core/src/main/java/org/teavm/backend/javascript/spi/Generator.java
+++ b/core/src/main/java/org/teavm/backend/javascript/spi/Generator.java
@@ -15,10 +15,9 @@
  */
 package org.teavm.backend.javascript.spi;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.model.MethodReference;
 
 public interface Generator {
-    void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException;
+    void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef);
 }
diff --git a/core/src/main/java/org/teavm/backend/javascript/spi/Injector.java b/core/src/main/java/org/teavm/backend/javascript/spi/Injector.java
index 05609efae..e49bf5ce7 100644
--- a/core/src/main/java/org/teavm/backend/javascript/spi/Injector.java
+++ b/core/src/main/java/org/teavm/backend/javascript/spi/Injector.java
@@ -15,9 +15,8 @@
  */
 package org.teavm.backend.javascript.spi;
 
-import java.io.IOException;
 import org.teavm.model.MethodReference;
 
 public interface Injector {
-    void generate(InjectorContext context, MethodReference methodRef) throws IOException;
+    void generate(InjectorContext context, MethodReference methodRef);
 }
diff --git a/core/src/main/java/org/teavm/backend/javascript/spi/InjectorContext.java b/core/src/main/java/org/teavm/backend/javascript/spi/InjectorContext.java
index 8facb3ec9..d3dd88b8c 100644
--- a/core/src/main/java/org/teavm/backend/javascript/spi/InjectorContext.java
+++ b/core/src/main/java/org/teavm/backend/javascript/spi/InjectorContext.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.backend.javascript.spi;
 
-import java.io.IOException;
 import java.util.Properties;
 import org.teavm.ast.Expr;
 import org.teavm.backend.javascript.codegen.SourceWriter;
@@ -37,9 +36,9 @@ public interface InjectorContext extends ServiceRepository {
 
     Properties getProperties();
 
-    void writeEscaped(String str) throws IOException;
+    void writeEscaped(String str);
 
-    void writeType(ValueType type) throws IOException;
+    void writeType(ValueType type);
 
     void writeExpr(Expr expr);
 
diff --git a/core/src/main/java/org/teavm/backend/javascript/templating/JavaScriptTemplateFactory.java b/core/src/main/java/org/teavm/backend/javascript/templating/JavaScriptTemplateFactory.java
index a941c310a..0fa3843b1 100644
--- a/core/src/main/java/org/teavm/backend/javascript/templating/JavaScriptTemplateFactory.java
+++ b/core/src/main/java/org/teavm/backend/javascript/templating/JavaScriptTemplateFactory.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.backend.javascript.templating;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.ast.AstUtil;
 import org.teavm.model.ClassReaderSource;
 
@@ -28,7 +27,7 @@ public class JavaScriptTemplateFactory {
         this.classSource = classSource;
     }
 
-    public JavaScriptTemplate createFromResource(String path) throws IOException {
+    public JavaScriptTemplate createFromResource(String path) {
         return new JavaScriptTemplate(AstUtil.parseFromResources(classLoader, path), classSource);
     }
 }
diff --git a/core/src/main/java/org/teavm/backend/javascript/templating/SourceFragment.java b/core/src/main/java/org/teavm/backend/javascript/templating/SourceFragment.java
index e405f862e..c954930ce 100644
--- a/core/src/main/java/org/teavm/backend/javascript/templating/SourceFragment.java
+++ b/core/src/main/java/org/teavm/backend/javascript/templating/SourceFragment.java
@@ -15,9 +15,8 @@
  */
 package org.teavm.backend.javascript.templating;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 
 public interface SourceFragment {
-    void write(SourceWriter writer, int precedence) throws IOException;
+    void write(SourceWriter writer, int precedence);
 }
diff --git a/core/src/main/java/org/teavm/backend/javascript/templating/TemplatingAstWriter.java b/core/src/main/java/org/teavm/backend/javascript/templating/TemplatingAstWriter.java
index b109e3cf8..7e8504bb8 100644
--- a/core/src/main/java/org/teavm/backend/javascript/templating/TemplatingAstWriter.java
+++ b/core/src/main/java/org/teavm/backend/javascript/templating/TemplatingAstWriter.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.backend.javascript.templating;
 
-import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
 import org.mozilla.javascript.ast.ElementGet;
@@ -56,7 +55,7 @@ public class TemplatingAstWriter extends AstWriter {
     }
 
     @Override
-    protected boolean intrinsic(FunctionCall node, int precedence) throws IOException {
+    protected boolean intrinsic(FunctionCall node, int precedence) {
         if (node.getTarget() instanceof Name) {
             var name = (Name) node.getTarget();
             if (scopeOfId(name.getIdentifier()) == null) {
@@ -66,7 +65,7 @@ public class TemplatingAstWriter extends AstWriter {
         return super.intrinsic(node, precedence);
     }
 
-    private boolean tryIntrinsicName(FunctionCall node, String name) throws IOException {
+    private boolean tryIntrinsicName(FunctionCall node, String name) {
         switch (name) {
             case "teavm_javaClass":
                 return writeJavaClass(node);
@@ -83,7 +82,7 @@ public class TemplatingAstWriter extends AstWriter {
         }
     }
 
-    private boolean writeJavaClass(FunctionCall node) throws IOException {
+    private boolean writeJavaClass(FunctionCall node) {
         if (node.getArguments().size() != 1) {
             return false;
         }
@@ -95,7 +94,7 @@ public class TemplatingAstWriter extends AstWriter {
         return true;
     }
 
-    private boolean writeJavaMethod(FunctionCall node) throws IOException {
+    private boolean writeJavaMethod(FunctionCall node) {
         if (node.getArguments().size() != 2) {
             return false;
         }
@@ -110,7 +109,7 @@ public class TemplatingAstWriter extends AstWriter {
         return true;
     }
 
-    private boolean writeJavaConstructor(FunctionCall node) throws IOException {
+    private boolean writeJavaConstructor(FunctionCall node) {
         if (node.getArguments().size() != 2) {
             return false;
         }
@@ -125,7 +124,7 @@ public class TemplatingAstWriter extends AstWriter {
         return true;
     }
 
-    private boolean writeJavaClassInit(FunctionCall node) throws IOException {
+    private boolean writeJavaClassInit(FunctionCall node) {
         if (node.getArguments().size() != 1) {
             return false;
         }
@@ -137,7 +136,7 @@ public class TemplatingAstWriter extends AstWriter {
         return true;
     }
 
-    private boolean writeFragment(FunctionCall node) throws IOException {
+    private boolean writeFragment(FunctionCall node) {
         if (node.getArguments().size() != 1) {
             return false;
         }
@@ -151,7 +150,7 @@ public class TemplatingAstWriter extends AstWriter {
     }
 
     @Override
-    protected void print(ElementGet node) throws IOException {
+    protected void print(ElementGet node) {
         if (node.getElement() instanceof FunctionCall) {
             var call = (FunctionCall) node.getElement();
             if (call.getTarget() instanceof Name) {
@@ -176,7 +175,7 @@ public class TemplatingAstWriter extends AstWriter {
     }
 
     @Override
-    public void print(PropertyGet node) throws IOException {
+    public void print(PropertyGet node) {
         if (node.getTarget() instanceof Name) {
             var name = (Name) node.getTarget();
             var scope = scopeOfId(name.getIdentifier());
@@ -192,7 +191,7 @@ public class TemplatingAstWriter extends AstWriter {
         super.print(node);
     }
 
-    private boolean writeJavaVirtualMethod(ElementGet get, FunctionCall call) throws IOException {
+    private boolean writeJavaVirtualMethod(ElementGet get, FunctionCall call) {
         var arg = call.getArguments().get(0);
         if (!(arg instanceof StringLiteral)) {
             return false;
@@ -203,7 +202,7 @@ public class TemplatingAstWriter extends AstWriter {
         return true;
     }
 
-    private boolean writeJavaField(ElementGet get, FunctionCall call) throws IOException {
+    private boolean writeJavaField(ElementGet get, FunctionCall call) {
         if (call.getArguments().size() != 2) {
             return false;
         }
@@ -220,7 +219,7 @@ public class TemplatingAstWriter extends AstWriter {
     }
 
     @Override
-    public void print(Name node, int precedence) throws IOException {
+    public void print(Name node, int precedence) {
         var definingScope = scopeOfId(node.getIdentifier());
         if (rootScope) {
             if (names != null && definingScope == scope) {
diff --git a/core/src/main/java/org/teavm/vm/spi/AbstractRendererListener.java b/core/src/main/java/org/teavm/vm/spi/AbstractRendererListener.java
index 3eef3ffdd..61e6fef60 100644
--- a/core/src/main/java/org/teavm/vm/spi/AbstractRendererListener.java
+++ b/core/src/main/java/org/teavm/vm/spi/AbstractRendererListener.java
@@ -15,16 +15,15 @@
  */
 package org.teavm.vm.spi;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.rendering.RenderingManager;
 import org.teavm.vm.BuildTarget;
 
 public abstract class AbstractRendererListener implements RendererListener {
     @Override
-    public void begin(RenderingManager manager, BuildTarget buildTarget) throws IOException {
+    public void begin(RenderingManager manager, BuildTarget buildTarget) {
     }
 
     @Override
-    public void complete() throws IOException {
+    public void complete() {
     }
 }
diff --git a/core/src/main/java/org/teavm/vm/spi/RendererListener.java b/core/src/main/java/org/teavm/vm/spi/RendererListener.java
index 1535b5b8f..50e082534 100644
--- a/core/src/main/java/org/teavm/vm/spi/RendererListener.java
+++ b/core/src/main/java/org/teavm/vm/spi/RendererListener.java
@@ -15,12 +15,11 @@
  */
 package org.teavm.vm.spi;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.rendering.RenderingManager;
 import org.teavm.vm.BuildTarget;
 
 public interface RendererListener {
-    void begin(RenderingManager context, BuildTarget buildTarget) throws IOException;
+    void begin(RenderingManager context, BuildTarget buildTarget);
 
-    void complete() throws IOException;
+    void complete();
 }
diff --git a/jso/impl/src/main/java/org/teavm/jso/impl/JSAliasRenderer.java b/jso/impl/src/main/java/org/teavm/jso/impl/JSAliasRenderer.java
index 1824fa399..27b5902bc 100644
--- a/jso/impl/src/main/java/org/teavm/jso/impl/JSAliasRenderer.java
+++ b/jso/impl/src/main/java/org/teavm/jso/impl/JSAliasRenderer.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.jso.impl;
 
-import java.io.IOException;
 import java.util.HashMap;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.rendering.RenderingManager;
@@ -44,7 +43,7 @@ class JSAliasRenderer implements RendererListener, VirtualMethodContributor {
     }
 
     @Override
-    public void complete() throws IOException {
+    public void complete() {
         if (!hasClassesToExpose()) {
             return;
         }
@@ -178,7 +177,7 @@ class JSAliasRenderer implements RendererListener, VirtualMethodContributor {
         }
     }
 
-    private void writeFunctor(ClassReader cls, FieldReference functorField) throws IOException {
+    private void writeFunctor(ClassReader cls, FieldReference functorField) {
         AnnotationReader implAnnot = cls.getAnnotations().get(FunctorImpl.class.getName());
         MethodDescriptor functorMethod = MethodDescriptor.parse(implAnnot.getValue("value").getString());
         String alias = cls.getMethod(functorMethod).getAnnotations()
@@ -206,7 +205,7 @@ class JSAliasRenderer implements RendererListener, VirtualMethodContributor {
         writer.outdent().append("};").softNewLine();
     }
 
-    private void appendArguments(int count) throws IOException {
+    private void appendArguments(int count) {
         for (int i = 0; i < count; ++i) {
             if (i > 0) {
                 writer.append(',').ws();
diff --git a/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyAstEmitter.java b/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyAstEmitter.java
index 497164c3e..2d3c5e704 100644
--- a/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyAstEmitter.java
+++ b/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyAstEmitter.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.jso.impl;
 
-import java.io.IOException;
 import org.mozilla.javascript.Node;
 import org.mozilla.javascript.ast.AstNode;
 import org.mozilla.javascript.ast.Block;
@@ -44,7 +43,7 @@ class JSBodyAstEmitter implements JSBodyEmitter {
     }
 
     @Override
-    public void emit(InjectorContext context) throws IOException {
+    public void emit(InjectorContext context) {
         var astWriter = new AstWriter(context.getWriter(), new DefaultGlobalNameWriter(context.getWriter()));
         int paramIndex = 0;
         if (!isStatic) {
@@ -148,7 +147,7 @@ class JSBodyAstEmitter implements JSBodyEmitter {
     }
 
     @Override
-    public void emit(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void emit(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         var astWriter = new AstWriter(writer, new DefaultGlobalNameWriter(writer));
         int paramIndex = 1;
         if (!isStatic) {
diff --git a/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyBloatedEmitter.java b/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyBloatedEmitter.java
index 287bdc382..586c4b206 100644
--- a/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyBloatedEmitter.java
+++ b/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyBloatedEmitter.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.jso.impl;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.GeneratorContext;
 import org.teavm.backend.javascript.spi.InjectorContext;
@@ -38,7 +37,7 @@ class JSBodyBloatedEmitter implements JSBodyEmitter {
     }
 
     @Override
-    public void emit(InjectorContext context) throws IOException {
+    public void emit(InjectorContext context) {
         emit(context.getWriter(), new EmissionStrategy() {
             @Override
             public void emitArgument(int argument) {
@@ -46,28 +45,28 @@ class JSBodyBloatedEmitter implements JSBodyEmitter {
             }
 
             @Override
-            public void emitModule(String name) throws IOException {
+            public void emitModule(String name) {
                 context.getWriter().append(context.importModule(name));
             }
         });
     }
 
     @Override
-    public void emit(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void emit(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         emit(writer, new EmissionStrategy() {
             @Override
-            public void emitArgument(int argument) throws IOException {
+            public void emitArgument(int argument) {
                 writer.append(context.getParameterName(argument + 1));
             }
 
             @Override
-            public void emitModule(String name) throws IOException {
+            public void emitModule(String name) {
                 writer.append(context.importModule(name));
             }
         });
     }
 
-    private void emit(SourceWriter writer, EmissionStrategy strategy) throws IOException {
+    private void emit(SourceWriter writer, EmissionStrategy strategy) {
         int bodyParamCount = isStatic ? method.parameterCount() : method.parameterCount() - 1;
 
         writer.append("if (!").appendMethodBody(method).append(".$native)").ws().append('{').indent().newLine();
@@ -151,8 +150,8 @@ class JSBodyBloatedEmitter implements JSBodyEmitter {
     }
 
     interface EmissionStrategy {
-        void emitArgument(int argument) throws IOException;
+        void emitArgument(int argument);
 
-        void emitModule(String name) throws IOException;
+        void emitModule(String name);
     }
 }
diff --git a/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyEmitter.java b/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyEmitter.java
index ec1f4a763..4cb5fc7e5 100644
--- a/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyEmitter.java
+++ b/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyEmitter.java
@@ -15,14 +15,13 @@
  */
 package org.teavm.jso.impl;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.GeneratorContext;
 import org.teavm.backend.javascript.spi.InjectorContext;
 import org.teavm.model.MethodReference;
 
 interface JSBodyEmitter {
-    void emit(InjectorContext context) throws IOException;
+    void emit(InjectorContext context);
 
-    void emit(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException;
+    void emit(GeneratorContext context, SourceWriter writer, MethodReference methodRef);
 }
diff --git a/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyGenerator.java b/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyGenerator.java
index ac6597f9f..8109863e1 100644
--- a/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyGenerator.java
+++ b/jso/impl/src/main/java/org/teavm/jso/impl/JSBodyGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.jso.impl;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.Generator;
 import org.teavm.backend.javascript.spi.GeneratorContext;
@@ -25,14 +24,14 @@ import org.teavm.model.MethodReference;
 
 public class JSBodyGenerator implements Injector, Generator {
     @Override
-    public void generate(InjectorContext context, MethodReference methodRef) throws IOException {
+    public void generate(InjectorContext context, MethodReference methodRef) {
         JSBodyRepository emitterRepository = context.getService(JSBodyRepository.class);
         JSBodyEmitter emitter = emitterRepository.emitters.get(methodRef);
         emitter.emit(context);
     }
 
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         JSBodyRepository emitterRepository = context.getService(JSBodyRepository.class);
         JSBodyEmitter emitter = emitterRepository.emitters.get(methodRef);
         emitter.emit(context, writer, methodRef);
diff --git a/jso/impl/src/main/java/org/teavm/jso/impl/JSExceptionsGenerator.java b/jso/impl/src/main/java/org/teavm/jso/impl/JSExceptionsGenerator.java
index b4ee6f805..b0d52c031 100644
--- a/jso/impl/src/main/java/org/teavm/jso/impl/JSExceptionsGenerator.java
+++ b/jso/impl/src/main/java/org/teavm/jso/impl/JSExceptionsGenerator.java
@@ -15,14 +15,13 @@
  */
 package org.teavm.jso.impl;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.spi.Injector;
 import org.teavm.backend.javascript.spi.InjectorContext;
 import org.teavm.model.MethodReference;
 
 public class JSExceptionsGenerator implements Injector {
     @Override
-    public void generate(InjectorContext context, MethodReference methodRef) throws IOException {
+    public void generate(InjectorContext context, MethodReference methodRef) {
         switch (methodRef.getName()) {
             case "getJavaException":
                 context.getWriter().appendFunction("$rt_javaException").append("(");
diff --git a/jso/impl/src/main/java/org/teavm/jso/impl/JSNativeGenerator.java b/jso/impl/src/main/java/org/teavm/jso/impl/JSNativeGenerator.java
index 2e79462eb..f90ef9cd7 100644
--- a/jso/impl/src/main/java/org/teavm/jso/impl/JSNativeGenerator.java
+++ b/jso/impl/src/main/java/org/teavm/jso/impl/JSNativeGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.jso.impl;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.Generator;
 import org.teavm.backend.javascript.spi.GeneratorContext;
@@ -26,13 +25,12 @@ import org.teavm.model.MethodReference;
 public class JSNativeGenerator implements Generator {
     private JavaScriptTemplate template;
 
-    public JSNativeGenerator(JavaScriptTemplateFactory templateFactory) throws IOException {
+    public JSNativeGenerator(JavaScriptTemplateFactory templateFactory) {
         template = templateFactory.createFromResource("org/teavm/jso/impl/JS.js");
     }
 
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef)
-            throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         switch (methodRef.getName()) {
             case "function":
                 template.builder("jsFunction").withContext(context).build().write(writer, 0);
diff --git a/jso/impl/src/main/java/org/teavm/jso/impl/JSNativeInjector.java b/jso/impl/src/main/java/org/teavm/jso/impl/JSNativeInjector.java
index 23d8e5645..cf000048f 100644
--- a/jso/impl/src/main/java/org/teavm/jso/impl/JSNativeInjector.java
+++ b/jso/impl/src/main/java/org/teavm/jso/impl/JSNativeInjector.java
@@ -16,7 +16,6 @@
 package org.teavm.jso.impl;
 
 import static org.teavm.backend.javascript.rendering.RenderingUtil.escapeString;
-import java.io.IOException;
 import java.util.HashSet;
 import java.util.Set;
 import org.teavm.ast.ConstantExpr;
@@ -41,7 +40,7 @@ public class JSNativeInjector implements Injector, DependencyPlugin {
     private Set<DependencyNode> functorParamNodes = new HashSet<>();
 
     @Override
-    public void generate(InjectorContext context, MethodReference methodRef) throws IOException {
+    public void generate(InjectorContext context, MethodReference methodRef) {
         SourceWriter writer = context.getWriter();
         switch (methodRef.getName()) {
             case "arrayData":
@@ -162,7 +161,7 @@ public class JSNativeInjector implements Injector, DependencyPlugin {
         }
     }
 
-    private void dataToArray(InjectorContext context, String className) throws IOException {
+    private void dataToArray(InjectorContext context, String className) {
         var writer = context.getWriter();
         writer.appendFunction("$rt_wrapArray").append("(").appendFunction(className).append(",").ws();
         context.writeExpr(context.getArgument(0), Precedence.min());
@@ -229,7 +228,7 @@ public class JSNativeInjector implements Injector, DependencyPlugin {
     }
 
 
-    private void renderProperty(Expr property, InjectorContext context) throws IOException {
+    private void renderProperty(Expr property, InjectorContext context) {
         SourceWriter writer = context.getWriter();
         String name = extractPropertyName(property);
         if (name == null) {
diff --git a/jso/impl/src/main/java/org/teavm/jso/impl/JSWrapperGenerator.java b/jso/impl/src/main/java/org/teavm/jso/impl/JSWrapperGenerator.java
index 09f277faa..f1c4ad2eb 100644
--- a/jso/impl/src/main/java/org/teavm/jso/impl/JSWrapperGenerator.java
+++ b/jso/impl/src/main/java/org/teavm/jso/impl/JSWrapperGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.jso.impl;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.rendering.Precedence;
 import org.teavm.backend.javascript.spi.Injector;
 import org.teavm.backend.javascript.spi.InjectorContext;
@@ -29,7 +28,7 @@ public class JSWrapperGenerator implements Injector, DependencyPlugin {
     private DependencyNode externalClassesNode;
 
     @Override
-    public void generate(InjectorContext context, MethodReference methodRef) throws IOException {
+    public void generate(InjectorContext context, MethodReference methodRef) {
         switch (methodRef.getName()) {
             case "directJavaToJs":
             case "directJsToJava":
diff --git a/platform/src/main/java/org/teavm/platform/plugin/AsyncMethodGenerator.java b/platform/src/main/java/org/teavm/platform/plugin/AsyncMethodGenerator.java
index f49414346..2d3e6bd84 100644
--- a/platform/src/main/java/org/teavm/platform/plugin/AsyncMethodGenerator.java
+++ b/platform/src/main/java/org/teavm/platform/plugin/AsyncMethodGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.platform.plugin;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.Generator;
 import org.teavm.backend.javascript.spi.GeneratorContext;
@@ -41,7 +40,7 @@ public class AsyncMethodGenerator implements Generator, DependencyPlugin, Virtua
     private JavaScriptTemplate template;
 
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         if (template == null) {
             var templateFactory = new JavaScriptTemplateFactory(context.getClassLoader(), context.getClassSource());
             template = templateFactory.createFromResource("org/teavm/platform/plugin/Async.js");
diff --git a/platform/src/main/java/org/teavm/platform/plugin/BuildTimeResourceArray.java b/platform/src/main/java/org/teavm/platform/plugin/BuildTimeResourceArray.java
index 451a79618..194ee101c 100644
--- a/platform/src/main/java/org/teavm/platform/plugin/BuildTimeResourceArray.java
+++ b/platform/src/main/java/org/teavm/platform/plugin/BuildTimeResourceArray.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.platform.plugin;
 
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import org.teavm.backend.javascript.codegen.SourceWriter;
@@ -41,7 +40,7 @@ class BuildTimeResourceArray<T extends Resource> implements ResourceArray<T>, Re
     }
 
     @Override
-    public void write(SourceWriter writer) throws IOException {
+    public void write(SourceWriter writer) {
         writer.append('[').tokenBoundary();
         for (int i = 0; i < data.size(); ++i) {
             if (i > 0) {
diff --git a/platform/src/main/java/org/teavm/platform/plugin/BuildTimeResourceMap.java b/platform/src/main/java/org/teavm/platform/plugin/BuildTimeResourceMap.java
index 91317c92f..7e1a77b43 100644
--- a/platform/src/main/java/org/teavm/platform/plugin/BuildTimeResourceMap.java
+++ b/platform/src/main/java/org/teavm/platform/plugin/BuildTimeResourceMap.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.platform.plugin;
 
-import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
 import org.teavm.backend.javascript.codegen.SourceWriter;
@@ -42,7 +41,7 @@ class BuildTimeResourceMap<T extends Resource> implements ResourceMap<T>, Resour
     }
 
     @Override
-    public void write(SourceWriter writer) throws IOException {
+    public void write(SourceWriter writer) {
         writer.append('{');
         boolean first = true;
         for (Map.Entry<String, T> entry : data.entrySet()) {
diff --git a/platform/src/main/java/org/teavm/platform/plugin/BuildTimeStaticFieldResource.java b/platform/src/main/java/org/teavm/platform/plugin/BuildTimeStaticFieldResource.java
index bfa67491c..b535bea79 100644
--- a/platform/src/main/java/org/teavm/platform/plugin/BuildTimeStaticFieldResource.java
+++ b/platform/src/main/java/org/teavm/platform/plugin/BuildTimeStaticFieldResource.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.platform.plugin;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.model.FieldReference;
 import org.teavm.platform.metadata.StaticFieldResource;
@@ -32,7 +31,7 @@ class BuildTimeStaticFieldResource implements StaticFieldResource, ResourceWrite
     }
 
     @Override
-    public void write(SourceWriter writer) throws IOException {
+    public void write(SourceWriter writer) {
         writer.appendField(field);
     }
 }
diff --git a/platform/src/main/java/org/teavm/platform/plugin/MetadataProviderNativeGenerator.java b/platform/src/main/java/org/teavm/platform/plugin/MetadataProviderNativeGenerator.java
index 21c22dae1..32d5bff67 100644
--- a/platform/src/main/java/org/teavm/platform/plugin/MetadataProviderNativeGenerator.java
+++ b/platform/src/main/java/org/teavm/platform/plugin/MetadataProviderNativeGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.platform.plugin;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.Generator;
 import org.teavm.backend.javascript.spi.GeneratorContext;
@@ -33,7 +32,7 @@ class MetadataProviderNativeGenerator implements Generator {
     }
 
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         DefaultMetadataGeneratorContext metadataContext = new DefaultMetadataGeneratorContext(context.getClassSource(),
                 context.getClassLoader(), context.getProperties(), context);
 
diff --git a/platform/src/main/java/org/teavm/platform/plugin/PlatformGenerator.java b/platform/src/main/java/org/teavm/platform/plugin/PlatformGenerator.java
index 8b37339fe..ee0c358e9 100644
--- a/platform/src/main/java/org/teavm/platform/plugin/PlatformGenerator.java
+++ b/platform/src/main/java/org/teavm/platform/plugin/PlatformGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.platform.plugin;
 
-import java.io.IOException;
 import java.lang.annotation.Annotation;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.Generator;
@@ -75,7 +74,7 @@ public class PlatformGenerator implements Generator, Injector, DependencyPlugin
     }
 
     @Override
-    public void generate(InjectorContext context, MethodReference methodRef) throws IOException {
+    public void generate(InjectorContext context, MethodReference methodRef) {
         switch (methodRef.getName()) {
             case "asJavaClass":
             case "classFromResource":
@@ -92,7 +91,7 @@ public class PlatformGenerator implements Generator, Injector, DependencyPlugin
     }
 
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         switch (methodRef.getName()) {
             case "prepareNewInstance":
                 generatePrepareNewInstance(context, writer);
@@ -112,8 +111,7 @@ public class PlatformGenerator implements Generator, Injector, DependencyPlugin
         }
     }
 
-    private void generateWithTemplate(GeneratorContext context, SourceWriter writer, MethodReference methodRef)
-            throws IOException {
+    private void generateWithTemplate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         if (template == null) {
             template = new JavaScriptTemplateFactory(context.getClassLoader(), context.getClassSource())
                     .createFromResource("org/teavm/platform/plugin/Platform.js");
@@ -121,7 +119,7 @@ public class PlatformGenerator implements Generator, Injector, DependencyPlugin
         template.builder(methodRef.getName()).withContext(context).build().write(writer, 0);
     }
 
-    private void generatePrepareNewInstance(GeneratorContext context, SourceWriter writer) throws IOException {
+    private void generatePrepareNewInstance(GeneratorContext context, SourceWriter writer) {
         MethodDependencyInfo newInstanceMethod = context.getDependency().getMethod(
                 new MethodReference(Platform.class, "newInstanceImpl", PlatformClass.class, Object.class));
         writer.append("let c").ws().append("=").ws().append("'$$constructor$$';").softNewLine();
@@ -140,7 +138,7 @@ public class PlatformGenerator implements Generator, Injector, DependencyPlugin
         }
     }
 
-    private void generateLookup(GeneratorContext context, SourceWriter writer) throws IOException {
+    private void generateLookup(GeneratorContext context, SourceWriter writer) {
         String param = context.getParameterName(1);
         writer.append("switch").ws().append("(").appendFunction("$rt_ustr").append("(" + param + "))")
                 .ws().append("{").softNewLine().indent();
@@ -153,7 +151,7 @@ public class PlatformGenerator implements Generator, Injector, DependencyPlugin
     }
 
 
-    private void generateEnumConstants(GeneratorContext context, SourceWriter writer) throws IOException {
+    private void generateEnumConstants(GeneratorContext context, SourceWriter writer) {
         writer.append("let c").ws().append("=").ws().append("'$$enumConstants$$';").softNewLine();
         for (String clsName : context.getClassSource().getClassNames()) {
             ClassReader cls = context.getClassSource().get(clsName);
@@ -184,7 +182,7 @@ public class PlatformGenerator implements Generator, Injector, DependencyPlugin
                 .append(");").softNewLine();
     }
 
-    private void generateAnnotations(GeneratorContext context, SourceWriter writer) throws IOException {
+    private void generateAnnotations(GeneratorContext context, SourceWriter writer) {
         writer.append("let c").ws().append("=").ws().append("'$$annotations$$';").softNewLine();
         for (String clsName : context.getClassSource().getClassNames()) {
             ClassReader annotCls = context.getClassSource().get(clsName + "$$__annotations__$$");
diff --git a/platform/src/main/java/org/teavm/platform/plugin/PlatformQueueGenerator.java b/platform/src/main/java/org/teavm/platform/plugin/PlatformQueueGenerator.java
index 8541c36ae..8546fa5e5 100644
--- a/platform/src/main/java/org/teavm/platform/plugin/PlatformQueueGenerator.java
+++ b/platform/src/main/java/org/teavm/platform/plugin/PlatformQueueGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.platform.plugin;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.spi.Injector;
 import org.teavm.backend.javascript.spi.InjectorContext;
 import org.teavm.dependency.DependencyAgent;
@@ -34,7 +33,7 @@ public class PlatformQueueGenerator implements Injector, DependencyPlugin {
     }
 
     @Override
-    public void generate(InjectorContext context, MethodReference methodRef) throws IOException {
+    public void generate(InjectorContext context, MethodReference methodRef) {
         context.writeExpr(context.getArgument(0));
     }
 }
diff --git a/platform/src/main/java/org/teavm/platform/plugin/ResourceAccessorGenerator.java b/platform/src/main/java/org/teavm/platform/plugin/ResourceAccessorGenerator.java
index 4d0a1802e..7413c7da1 100644
--- a/platform/src/main/java/org/teavm/platform/plugin/ResourceAccessorGenerator.java
+++ b/platform/src/main/java/org/teavm/platform/plugin/ResourceAccessorGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.platform.plugin;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.spi.Generator;
 import org.teavm.backend.javascript.spi.GeneratorContext;
@@ -23,7 +22,7 @@ import org.teavm.model.MethodReference;
 
 class ResourceAccessorGenerator implements Generator {
     @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
+    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) {
         writer.append("let result").ws().append("=").ws().append("[];").softNewLine();
         writer.append("for").ws().append("(let key in ").append(context.getParameterName(1)).append(")").ws()
                 .append("{").indent().softNewLine();
diff --git a/platform/src/main/java/org/teavm/platform/plugin/ResourceAccessorInjector.java b/platform/src/main/java/org/teavm/platform/plugin/ResourceAccessorInjector.java
index 955748751..b7d0d1598 100644
--- a/platform/src/main/java/org/teavm/platform/plugin/ResourceAccessorInjector.java
+++ b/platform/src/main/java/org/teavm/platform/plugin/ResourceAccessorInjector.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.platform.plugin;
 
-import java.io.IOException;
 import org.teavm.ast.ConstantExpr;
 import org.teavm.ast.Expr;
 import org.teavm.backend.javascript.spi.Injector;
@@ -25,7 +24,7 @@ import org.teavm.model.ValueType;
 
 class ResourceAccessorInjector implements Injector {
     @Override
-    public void generate(InjectorContext context, MethodReference methodRef) throws IOException {
+    public void generate(InjectorContext context, MethodReference methodRef) {
         switch (methodRef.getName()) {
             case "get":
             case "getProperty":
@@ -102,7 +101,7 @@ class ResourceAccessorInjector implements Injector {
         }
     }
 
-    private void writePropertyAccessor(InjectorContext context, Expr property) throws IOException {
+    private void writePropertyAccessor(InjectorContext context, Expr property) {
         if (property instanceof ConstantExpr) {
             String str = (String) ((ConstantExpr) property).getValue();
             if (str.isEmpty()) {
@@ -119,7 +118,7 @@ class ResourceAccessorInjector implements Injector {
         context.getWriter().append(")]");
     }
 
-    private void writeStringExpr(InjectorContext context, Expr expr) throws IOException {
+    private void writeStringExpr(InjectorContext context, Expr expr) {
         if (expr instanceof ConstantExpr) {
             String str = (String) ((ConstantExpr) expr).getValue();
             context.getWriter().append('"');
diff --git a/platform/src/main/java/org/teavm/platform/plugin/ResourceWriter.java b/platform/src/main/java/org/teavm/platform/plugin/ResourceWriter.java
index 5247b185c..c5447ecd5 100644
--- a/platform/src/main/java/org/teavm/platform/plugin/ResourceWriter.java
+++ b/platform/src/main/java/org/teavm/platform/plugin/ResourceWriter.java
@@ -15,9 +15,8 @@
  */
 package org.teavm.platform.plugin;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 
 public interface ResourceWriter {
-    void write(SourceWriter writer) throws IOException;
+    void write(SourceWriter writer);
 }
diff --git a/platform/src/main/java/org/teavm/platform/plugin/ResourceWriterHelper.java b/platform/src/main/java/org/teavm/platform/plugin/ResourceWriterHelper.java
index 09da2309a..9727414b1 100644
--- a/platform/src/main/java/org/teavm/platform/plugin/ResourceWriterHelper.java
+++ b/platform/src/main/java/org/teavm/platform/plugin/ResourceWriterHelper.java
@@ -23,7 +23,7 @@ final class ResourceWriterHelper {
     private ResourceWriterHelper() {
     }
 
-    public static void write(SourceWriter writer, Object resource) throws IOException {
+    public static void write(SourceWriter writer, Object resource) {
         if (resource == null) {
             writer.append("null");
         } else {
diff --git a/tests/src/test/java/org/teavm/incremental/EntryPointGenerator.java b/tests/src/test/java/org/teavm/incremental/EntryPointGenerator.java
index 96c6c200e..1dbca3292 100644
--- a/tests/src/test/java/org/teavm/incremental/EntryPointGenerator.java
+++ b/tests/src/test/java/org/teavm/incremental/EntryPointGenerator.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.incremental;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.spi.Injector;
 import org.teavm.backend.javascript.spi.InjectorContext;
 import org.teavm.model.FieldReference;
@@ -23,7 +22,7 @@ import org.teavm.model.MethodReference;
 
 public class EntryPointGenerator implements Injector {
     @Override
-    public void generate(InjectorContext context, MethodReference methodRef) throws IOException {
+    public void generate(InjectorContext context, MethodReference methodRef) {
         context.getWriter().append("main.result = (");
         context.writeExpr(context.getArgument(0));
         context.getWriter().append(").").appendField(new FieldReference("java.lang.String", "nativeString"));
diff --git a/tools/junit/src/main/java/org/teavm/junit/TestExceptionPlugin.java b/tools/junit/src/main/java/org/teavm/junit/TestExceptionPlugin.java
index c3807249b..b8a04fc99 100644
--- a/tools/junit/src/main/java/org/teavm/junit/TestExceptionPlugin.java
+++ b/tools/junit/src/main/java/org/teavm/junit/TestExceptionPlugin.java
@@ -15,7 +15,6 @@
  */
 package org.teavm.junit;
 
-import java.io.IOException;
 import org.teavm.backend.javascript.TeaVMJavaScriptHost;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.backend.javascript.rendering.RenderingManager;
@@ -51,18 +50,18 @@ class TestExceptionPlugin implements TeaVMPlugin {
             RenderingManager manager;
 
             @Override
-            public void begin(RenderingManager manager, BuildTarget buildTarget) throws IOException {
+            public void begin(RenderingManager manager, BuildTarget buildTarget) {
                 this.manager = manager;
             }
 
             @Override
-            public void complete() throws IOException {
+            public void complete() {
                 renderExceptionMessage(manager.getWriter());
             }
         });
     }
 
-    private void renderExceptionMessage(SourceWriter writer) throws IOException {
+    private void renderExceptionMessage(SourceWriter writer) {
         writer.appendClass("java.lang.Throwable").append(".prototype.getMessage").ws().append("=").ws()
                 .append("function()").ws().append("{").indent().softNewLine();
         writer.append("return ").appendFunction("$rt_ustr").append("(this.")