diff --git a/classlib/src/main/java/org/teavm/classlib/impl/PlatformMarkerSupport.java b/classlib/src/main/java/org/teavm/classlib/impl/PlatformMarkerSupport.java
index 84a53333b..91f56c1a9 100644
--- a/classlib/src/main/java/org/teavm/classlib/impl/PlatformMarkerSupport.java
+++ b/classlib/src/main/java/org/teavm/classlib/impl/PlatformMarkerSupport.java
@@ -65,12 +65,18 @@ public class PlatformMarkerSupport implements ClassHolderTransformer {
         for (BasicBlock block : program.getBasicBlocks()) {
             for (Instruction instruction : block) {
                 Variable receiver;
+                MarkerKind kind;
                 if (instruction instanceof InvokeInstruction) {
                     MethodReference methodRef = ((InvokeInstruction) instruction).getMethod();
                     MethodReader method = innerSource.resolve(methodRef);
-                    if (method == null || !isMarker(method)) {
+                    if (method == null) {
                         continue;
                     }
+                    kind = isMarker(method);
+                    if (kind == null) {
+                        continue;
+                    }
+
                     if (!method.hasModifier(ElementModifier.STATIC)) {
                         diagnostics.error(new CallLocation(containingMethod, instruction.getLocation()),
                                 "Method '{{m0}}' is marked with '{{c1}}' and should be static",
@@ -87,9 +93,14 @@ public class PlatformMarkerSupport implements ClassHolderTransformer {
                 } else if (instruction instanceof GetFieldInstruction) {
                     FieldReference fieldRef = ((GetFieldInstruction) instruction).getField();
                     FieldReader field = innerSource.resolve(fieldRef);
-                    if (field == null || !isMarker(field)) {
+                    if (field == null) {
                         continue;
                     }
+                    kind = isMarker(field);
+                    if (kind == null) {
+                        continue;
+                    }
+
                     if (!field.hasModifier(ElementModifier.STATIC)) {
                         diagnostics.error(new CallLocation(containingMethod, instruction.getLocation()),
                                 "Field '{{f0}}' is marked with '{{c1}}' and should be static",
@@ -113,7 +124,7 @@ public class PlatformMarkerSupport implements ClassHolderTransformer {
                 } else {
                     IntegerConstantInstruction trueResult = new IntegerConstantInstruction();
                     trueResult.setReceiver(receiver);
-                    trueResult.setConstant(1);
+                    trueResult.setConstant(kind == MarkerKind.TRUE ? 1 : 0);
                     trueResult.setLocation(instruction.getLocation());
                     instruction.replace(trueResult);
                 }
@@ -130,21 +141,26 @@ public class PlatformMarkerSupport implements ClassHolderTransformer {
         }
     }
 
-    private boolean isMarker(MemberReader member) {
+    private MarkerKind isMarker(MemberReader member) {
         AnnotationReader annot = member.getAnnotations().get(PlatformMarker.class.getName());
         if (annot == null) {
-            return false;
+            return null;
         }
         AnnotationValue value = annot.getValue("value");
         if (value == null) {
-            return true;
+            return MarkerKind.TRUE;
         }
         String tagToMatch = value.getString();
         for (String tag : tags) {
             if (tag.equals(tagToMatch)) {
-                return true;
+                return MarkerKind.TRUE;
             }
         }
-        return false;
+        return MarkerKind.FALSE;
+    }
+
+    enum MarkerKind {
+        TRUE,
+        FALSE
     }
 }
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TCharacter.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TCharacter.java
index 122689df5..488e1c541 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TCharacter.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TCharacter.java
@@ -242,7 +242,7 @@ public class TCharacter extends TObject implements TComparable<TCharacter> {
         return toLowerCaseSystem(codePoint);
     }
 
-    @Import(module = "runtime", name = "tolower")
+    @Import(module = "runtime", name = "towlower")
     private static native int toLowerCaseSystem(int codePoint);
 
     public static char toUpperCase(char ch) {
@@ -258,7 +258,7 @@ public class TCharacter extends TObject implements TComparable<TCharacter> {
         return toUpperCaseSystem(codePoint);
     }
 
-    @Import(module = "runtime", name = "toupper")
+    @Import(module = "runtime", name = "towupper")
     private static native int toUpperCaseSystem(int codePoint);
 
     public static int digit(char ch, int radix) {
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TClass.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TClass.java
index d99f7795b..7d90276a3 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TClass.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TClass.java
@@ -512,7 +512,11 @@ public class TClass<T> extends TObject implements TAnnotatedElement {
 
     @SuppressWarnings("unchecked")
     public T[] getEnumConstants() {
-        return isEnum() ? (T[]) Platform.getEnumConstants(platformClass).clone() : null;
+        if (!isEnum()) {
+            return null;
+        }
+        Platform.initClass(platformClass);
+        return (T[]) Platform.getEnumConstants(platformClass).clone();
     }
 
     @SuppressWarnings("unchecked")
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TConsoleOutputStreamStderr.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TConsoleOutputStreamStderr.java
index 5eb0a919c..530d7d2f5 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TConsoleOutputStreamStderr.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TConsoleOutputStreamStderr.java
@@ -32,6 +32,6 @@ class TConsoleOutputStreamStderr extends TOutputStream {
         writeImpl(b);
     }
 
-    @Import(name = "putchar", module = "runtime")
+    @Import(name = "putwchar", module = "runtime")
     static native void writeImpl(int b);
 }
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TDouble.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TDouble.java
index f046473b2..90e32736d 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TDouble.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TDouble.java
@@ -222,15 +222,15 @@ public class TDouble extends TNumber implements TComparable<TDouble> {
     }
 
     @JSBody(params = "v", script = "return isNaN(v);")
-    @Import(module = "runtime", name = "isNaN")
+    @Import(module = "runtime", name = "isnan")
     public static native boolean isNaN(double v);
 
     @JSBody(script = "return NaN;")
-    @Import(module = "runtime", name = "getNaN")
+    @Import(module = "runtime", name = "TeaVM_getNaN")
     private static native double getNaN();
 
     @JSBody(params = "v", script = "return !isFinite(v);")
-    @Import(module = "runtime", name = "isInfinite")
+    @Import(module = "runtime", name = "isinf")
     public static native boolean isInfinite(double v);
 
     public static long doubleToRawLongBits(double value) {
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TFloat.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TFloat.java
index ee9d6329d..feb1b993b 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TFloat.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TFloat.java
@@ -90,7 +90,7 @@ public class TFloat extends TNumber implements TComparable<TFloat> {
     }
 
     @JSBody(params = "v", script = "return isNaN(v);")
-    @Import(module = "runtime", name = "isNaN")
+    @Import(module = "runtime", name = "isnan")
     public static native boolean isNaN(float v);
 
     public static boolean isInfinite(float v) {
@@ -98,11 +98,11 @@ public class TFloat extends TNumber implements TComparable<TFloat> {
     }
 
     @JSBody(params = "v", script = "return isFinite(v);")
-    @Import(module = "runtime", name = "isFinite")
+    @Import(module = "runtime", name = "isfinite")
     private static native boolean isFinite(float v);
 
     @JSBody(script = "return NaN;")
-    @Import(module = "runtime", name = "getNaN")
+    @Import(module = "runtime", name = "TeaVM_getNaN")
     private static native float getNaN();
 
     public static float parseFloat(TString string) throws TNumberFormatException {
diff --git a/classlib/src/main/java/org/teavm/classlib/java/util/TRandom.java b/classlib/src/main/java/org/teavm/classlib/java/util/TRandom.java
index efcc92736..46530bafa 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/util/TRandom.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/util/TRandom.java
@@ -15,6 +15,7 @@
  */
 package org.teavm.classlib.java.util;
 
+import org.teavm.classlib.PlatformDetector;
 import org.teavm.classlib.java.io.TSerializable;
 import org.teavm.classlib.java.lang.TMath;
 import org.teavm.classlib.java.lang.TObject;
@@ -39,7 +40,7 @@ public class TRandom extends TObject implements TSerializable {
     }
 
     protected int next(int bits) {
-        return (int) (random() * (1L << TMath.min(32, bits)));
+        return (int) (nextDouble() * (1L << TMath.min(32, bits)));
     }
 
     public void nextBytes(byte[] bytes) {
@@ -53,7 +54,7 @@ public class TRandom extends TObject implements TSerializable {
     }
 
     public int nextInt(int n) {
-        return (int) (random() * n);
+        return (int) (nextDouble() * n);
     }
 
     public long nextLong() {
@@ -65,13 +66,20 @@ public class TRandom extends TObject implements TSerializable {
     }
 
     public float nextFloat() {
-        return (float) random();
+        return (float) nextDouble();
     }
 
     public double nextDouble() {
-        return random();
+        if (PlatformDetector.isC()) {
+            return crand();
+        } else {
+            return random();
+        }
     }
-    
+
+    @Import(name = "TeaVM_rand")
+    private static native double crand();
+
     /**
      * Generate a random number with Gaussian distribution:
      * centered around 0 with a standard deviation of 1.0.
diff --git a/core/src/main/java/org/teavm/backend/c/CTarget.java b/core/src/main/java/org/teavm/backend/c/CTarget.java
index 12a2b7f4a..10e65b349 100644
--- a/core/src/main/java/org/teavm/backend/c/CTarget.java
+++ b/core/src/main/java/org/teavm/backend/c/CTarget.java
@@ -352,6 +352,7 @@ public class CTarget implements TeaVMTarget {
             Set<? extends ValueType> types) {
         writer.println("int main(int argc, char** argv) {").indent();
 
+        writer.println("TeaVM_beforeInit();");
         writer.println("initHeap(" + minHeapSize + ");");
         generateVirtualTableHeaders(context, writer, types);
         generateStringPoolHeaders(context, writer);
@@ -417,6 +418,6 @@ public class CTarget implements TeaVMTarget {
 
     @Override
     public String[] getPlatformTags() {
-        return new String[] { PlatformMarkers.C, PlatformMarkers.WEBASSEMBLY };
+        return new String[] { PlatformMarkers.C, PlatformMarkers.LOW_LEVEL };
     }
 }
diff --git a/core/src/main/java/org/teavm/backend/c/generate/ClassGenerator.java b/core/src/main/java/org/teavm/backend/c/generate/ClassGenerator.java
index 45f9bbc98..328ab6443 100644
--- a/core/src/main/java/org/teavm/backend/c/generate/ClassGenerator.java
+++ b/core/src/main/java/org/teavm/backend/c/generate/ClassGenerator.java
@@ -22,6 +22,7 @@ import java.util.Arrays;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Set;
+import java.util.stream.Collectors;
 import org.teavm.ast.RegularMethodNode;
 import org.teavm.ast.decompilation.Decompiler;
 import org.teavm.backend.c.generators.Generator;
@@ -36,6 +37,7 @@ import org.teavm.model.ClassReader;
 import org.teavm.model.ClassReaderSource;
 import org.teavm.model.ElementModifier;
 import org.teavm.model.FieldHolder;
+import org.teavm.model.FieldReader;
 import org.teavm.model.FieldReference;
 import org.teavm.model.MethodDescriptor;
 import org.teavm.model.MethodHolder;
@@ -276,11 +278,20 @@ public class ClassGenerator {
         String name = context.getNames().forClassInstance(type);
 
         vtableForwardWriter.print("static ").print(structName).print(" ").print(name).println(";");
+
+        ClassReader cls = className != null ? context.getClassSource().get(className) : null;
+        String enumConstants;
+        if (cls != null && cls.hasModifier(ElementModifier.ENUM)) {
+            enumConstants = writeEnumConstants(cls, name);
+        } else {
+            enumConstants = "NULL";
+        }
+
         vtableWriter.print("static alignas(8) ").print(structName).print(" ").print(name).println(" = {").indent();
 
         if (className != null) {
             vtableWriter.println(".parent = {").indent();
-            generateRuntimeClassInitializer(type);
+            generateRuntimeClassInitializer(type, enumConstants);
             vtableWriter.outdent().println("},");
 
             VirtualTable virtualTable = context.getVirtualTableProvider().lookup(className);
@@ -301,19 +312,34 @@ public class ClassGenerator {
                 }
             }
         } else {
-            generateRuntimeClassInitializer(type);
+            generateRuntimeClassInitializer(type, enumConstants);
         }
 
         vtableWriter.outdent().println("};");
     }
 
-    private void generateRuntimeClassInitializer(ValueType type) {
+    private String writeEnumConstants(ClassReader cls, String baseName) {
+        List<FieldReader> fields = cls.getFields().stream()
+                .filter(f -> f.hasModifier(ElementModifier.ENUM))
+                .collect(Collectors.toList());
+        String name = baseName + "_enumConstants";
+        vtableWriter.print("static void* " + name + "[" + (fields.size() + 1) + "] = { ");
+        vtableWriter.print("(void*) (intptr_t) " + fields.size());
+        for (FieldReader field : fields) {
+            vtableWriter.print(", ").print("&" + context.getNames().forStaticField(field.getReference()));
+        }
+        vtableWriter.println(" };");
+        return name;
+    }
+
+    private void generateRuntimeClassInitializer(ValueType type, String enumConstants) {
         String sizeExpr;
         int tag;
         String parent;
         String itemTypeExpr;
         int flags = 0;
         String layout = "NULL";
+        String initFunction = "NULL";
 
         if (type instanceof ValueType.Object) {
             String className = ((ValueType.Object) type).getClassName();
@@ -323,13 +349,17 @@ public class ClassGenerator {
                 className = RuntimeObject.class.getName();
             }
 
-            if (needsData(cls)) {
+            if (cls != null && needsData(cls)) {
                 String structName = context.getNames().forClass(className);
                 sizeExpr = "(int32_t) (intptr_t) ALIGN(sizeof(" + structName + "), sizeof(void*))";
             } else {
                 sizeExpr = "0";
             }
-            tag = tagRegistry.getRanges(className).get(0).lower;
+            if (cls != null && cls.hasModifier(ElementModifier.ENUM)) {
+                flags |= RuntimeClass.ENUM;
+            }
+            List<TagRegistry.Range> ranges = tagRegistry.getRanges(className);
+            tag = ranges != null && !ranges.isEmpty() ? ranges.get(0).lower : 0;
 
             parent = cls != null && cls.getParent() != null && types.contains(ValueType.object(cls.getParent()))
                     ? "&" + context.getNames().forClassInstance(ValueType.object(cls.getParent()))
@@ -337,6 +367,10 @@ public class ClassGenerator {
             itemTypeExpr = "NULL";
             int layoutOffset = classLayoutOffsets.getOrDefault(className, -1);
             layout = layoutOffset >= 0 ? "classLayouts + " + layoutOffset : "NULL";
+
+            if (cls != null && needsInitializer(cls)) {
+                initFunction = context.getNames().forClassInitializer(className);
+            }
         } else if (type instanceof ValueType.Array) {
             parent = "&" + context.getNames().forClassInstance(ValueType.object("java.lang.Object"));
             tag = tagRegistry.getRanges("java.lang.Object").get(0).lower;
@@ -382,7 +416,9 @@ public class ClassGenerator {
         vtableWriter.print(".").print(classFieldName("isSupertypeOf")).println(" = &" + superTypeFunction + ",");
         vtableWriter.print(".").print(classFieldName("parent")).println(" = " + parent + ",");
         vtableWriter.print(".").print(classFieldName("enumValues")).println(" = NULL,");
-        vtableWriter.print(".").print(classFieldName("layout")).println(" = " + layout);
+        vtableWriter.print(".").print(classFieldName("layout")).println(" = " + layout + ",");
+        vtableWriter.print(".").print(classFieldName("enumValues")).println(" = " + enumConstants + ",");
+        vtableWriter.print(".").print(classFieldName("init")).println(" = " + initFunction);
     }
 
     private void generateVirtualTableStructure(ClassReader cls) {
@@ -392,13 +428,15 @@ public class ClassGenerator {
         vtableStructuresWriter.println("JavaClass parent;");
 
         VirtualTable virtualTable = context.getVirtualTableProvider().lookup(cls.getName());
-        for (VirtualTableEntry entry : virtualTable.getEntries().values()) {
-            String methodName = context.getNames().forVirtualMethod(
-                    new MethodReference(cls.getName(), entry.getMethod()));
-            vtableStructuresWriter.printType(entry.getMethod().getResultType())
-                    .print(" (*").print(methodName).print(")(");
-            codeGenerator.generateMethodParameters(vtableStructuresWriter, entry.getMethod(), false, false);
-            vtableStructuresWriter.println(");");
+        if (virtualTable != null) {
+            for (VirtualTableEntry entry : virtualTable.getEntries().values()) {
+                String methodName = context.getNames().forVirtualMethod(
+                        new MethodReference(cls.getName(), entry.getMethod()));
+                vtableStructuresWriter.printType(entry.getMethod().getResultType())
+                        .print(" (*").print(methodName).print(")(");
+                codeGenerator.generateMethodParameters(vtableStructuresWriter, entry.getMethod(), false, false);
+                vtableStructuresWriter.println(");");
+            }
         }
 
         vtableStructuresWriter.outdent().print("} ").print(name).println(";");
@@ -517,7 +555,7 @@ public class ClassGenerator {
         }
     }
 
-    private boolean needsInitializer(ClassHolder cls) {
+    private boolean needsInitializer(ClassReader cls) {
         return !context.getCharacteristics().isStaticInit(cls.getName())
                 && !context.getCharacteristics().isStructure(cls.getName())
                 && cls.getMethod(new MethodDescriptor("<clinit>", ValueType.VOID)) != null;
diff --git a/core/src/main/java/org/teavm/backend/c/generate/CodeGenerationVisitor.java b/core/src/main/java/org/teavm/backend/c/generate/CodeGenerationVisitor.java
index cd3d1eb65..f730e5cd5 100644
--- a/core/src/main/java/org/teavm/backend/c/generate/CodeGenerationVisitor.java
+++ b/core/src/main/java/org/teavm/backend/c/generate/CodeGenerationVisitor.java
@@ -266,13 +266,48 @@ public class CodeGenerationVisitor implements ExprVisitor, StatementVisitor {
             int index = context.getStringPool().getStringIndex((String) value);
             writer.print("(stringPool + " + index + ")");
         } else if (value instanceof Integer) {
-            writer.print("INT32_C(" + value + ")");
+            int i = (Integer) value;
+            long v = i;
+            if (i < 0) {
+                writer.print("-");
+                v = -i;
+            }
+            writer.print("INT32_C(");
+            writeLongConstant(v);
+            writer.print(")");
         } else if (value instanceof Long) {
-            writer.print("INT64_C(" + value + ")");
+            long v = (Long) value;
+            if (v < 0) {
+                writer.print("-");
+                v = -v;
+            }
+            writer.print("INT64_C(");
+            writeLongConstant(v);
+            writer.print(")");
         } else if (value instanceof Float) {
-            writer.print(value + "f");
+            float f = (Float) value;
+            if (Float.isInfinite(f)) {
+                if (f < 0) {
+                    writer.print("-");
+                }
+                writer.print("INFINITY");
+            } else if (Float.isNaN(f)) {
+                writer.print("NAN");
+            } else {
+                writer.print(f + "f");
+            }
         } else if (value instanceof Double) {
-            writer.print(value.toString());
+            double d = (Double) value;
+            if (Double.isInfinite(d)) {
+                if (d < 0) {
+                    writer.print("-");
+                }
+                writer.print("INFINITY");
+            } else if (Double.isNaN(d)) {
+                writer.print("NAN");
+            } else {
+                writer.print(value.toString());
+            }
         } else if (value instanceof Boolean) {
             writer.print((Boolean) value ? "1" : "0");
         } else if (value instanceof ValueType) {
@@ -280,6 +315,14 @@ public class CodeGenerationVisitor implements ExprVisitor, StatementVisitor {
         }
     }
 
+    private void writeLongConstant(long v) {
+        if (v == Long.MIN_VALUE) {
+            writer.print("0x8000000000000000");
+            return;
+        }
+        writer.print(String.valueOf(v));
+    }
+
     @Override
     public void visit(VariableExpr expr) {
         if (expr.getIndex() == 0) {
diff --git a/core/src/main/java/org/teavm/backend/c/intrinsic/PlatformClassMetadataIntrinsic.java b/core/src/main/java/org/teavm/backend/c/intrinsic/PlatformClassMetadataIntrinsic.java
index 7dfdff876..b65b81140 100644
--- a/core/src/main/java/org/teavm/backend/c/intrinsic/PlatformClassMetadataIntrinsic.java
+++ b/core/src/main/java/org/teavm/backend/c/intrinsic/PlatformClassMetadataIntrinsic.java
@@ -24,26 +24,40 @@ public class PlatformClassMetadataIntrinsic implements Intrinsic {
     private static final String PLATFORM_CLASS_METADATA = "org.teavm.platform.PlatformClassMetadata";
     private static final FieldReference ARRAY_TYPE_FIELD = new FieldReference(
             RuntimeClass.class.getName(), "arrayType");
+    private static final FieldReference SUPERCLASS_FIELD = new FieldReference(
+            RuntimeClass.class.getName(), "parent");
 
     @Override
     public boolean canHandle(MethodReference method) {
         if (!method.getClassName().equals(PLATFORM_CLASS_METADATA)) {
             return false;
         }
-        return method.getName().equals("getArrayItem");
+        switch (method.getName()) {
+            case "getArrayItem":
+            case "getSuperclass":
+                return true;
+        }
+        return false;
     }
 
     @Override
     public void apply(IntrinsicContext context, InvocationExpr invocation) {
         switch (invocation.getMethod().getName()) {
             case "getArrayItem":
-                context.writer().print("FIELD(");
-                context.emit(invocation.getArguments().get(0));
-                context.writer().print(",");
-                context.writer().print(context.names().forClass(ARRAY_TYPE_FIELD.getClassName())).print(", ");
-                context.writer().print(context.names().forMemberField(ARRAY_TYPE_FIELD));
-                context.writer().print(")");
+                printFieldAccess(context, invocation, ARRAY_TYPE_FIELD);
+                break;
+            case "getSuperclass":
+                printFieldAccess(context, invocation, SUPERCLASS_FIELD);
                 break;
         }
     }
+
+    private void printFieldAccess(IntrinsicContext context, InvocationExpr invocation, FieldReference field) {
+        context.writer().print("FIELD(");
+        context.emit(invocation.getArguments().get(0));
+        context.writer().print(",");
+        context.writer().print(context.names().forClass(field.getClassName())).print(", ");
+        context.writer().print(context.names().forMemberField(field));
+        context.writer().print(")");
+    }
 }
diff --git a/core/src/main/java/org/teavm/backend/c/intrinsic/PlatformIntrinsic.java b/core/src/main/java/org/teavm/backend/c/intrinsic/PlatformIntrinsic.java
index b248e242c..460d35676 100644
--- a/core/src/main/java/org/teavm/backend/c/intrinsic/PlatformIntrinsic.java
+++ b/core/src/main/java/org/teavm/backend/c/intrinsic/PlatformIntrinsic.java
@@ -42,8 +42,6 @@ public class PlatformIntrinsic implements Intrinsic {
             case "asJavaClass":
                 context.emit(invocation.getArguments().get(0));
                 break;
-            case "getName":
-
         }
     }
 }
diff --git a/core/src/main/java/org/teavm/runtime/InitFunction.java b/core/src/main/java/org/teavm/runtime/InitFunction.java
new file mode 100644
index 000000000..2c8d28c0c
--- /dev/null
+++ b/core/src/main/java/org/teavm/runtime/InitFunction.java
@@ -0,0 +1,24 @@
+/*
+ *  Copyright 2018 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.runtime;
+
+import org.teavm.interop.Function;
+import org.teavm.interop.Unmanaged;
+
+public abstract class InitFunction extends Function {
+    @Unmanaged
+    public abstract void run();
+}
diff --git a/core/src/main/java/org/teavm/runtime/RuntimeClass.java b/core/src/main/java/org/teavm/runtime/RuntimeClass.java
index f804eca84..ec139ad9f 100644
--- a/core/src/main/java/org/teavm/runtime/RuntimeClass.java
+++ b/core/src/main/java/org/teavm/runtime/RuntimeClass.java
@@ -43,6 +43,7 @@ public class RuntimeClass extends RuntimeObject {
     public RuntimeClass itemType;
     public RuntimeClass arrayType;
     public IsSupertypeFunction isSupertypeOf;
+    public InitFunction init;
     public RuntimeClass parent;
     public Address enumValues;
     public Address layout;
diff --git a/core/src/main/resources/org/teavm/backend/c/runtime.c b/core/src/main/resources/org/teavm/backend/c/runtime.c
index e73cfaf24..712126a6a 100644
--- a/core/src/main/resources/org/teavm/backend/c/runtime.c
+++ b/core/src/main/resources/org/teavm/backend/c/runtime.c
@@ -2,7 +2,9 @@
 #include <stdint.h>
 #include <stddef.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <uchar.h>
+#include <wchar.h>
 #include <time.h>
 #include <math.h>
 
@@ -87,6 +89,18 @@ static int32_t gc_regionSize = INT32_C(32768);
 static int32_t gc_regionMaxCount = INT32_C(0);
 static int64_t gc_availableBytes = INT64_C(0);
 
+static double TeaVM_rand() {
+    return rand() / ((double) RAND_MAX + 1);
+}
+
+static inline float TeaVM_getNaN() {
+    return NAN;
+}
+
+static void TeaVM_beforeInit() {
+    srand(time(NULL));
+}
+
 #ifdef __GNUC__
 static void initHeap(int64_t heapSize) {
     long workSize = heapSize / 16;
diff --git a/platform/src/main/java/org/teavm/platform/Platform.java b/platform/src/main/java/org/teavm/platform/Platform.java
index f8955a524..0eea8a94a 100644
--- a/platform/src/main/java/org/teavm/platform/Platform.java
+++ b/platform/src/main/java/org/teavm/platform/Platform.java
@@ -112,8 +112,16 @@ public final class Platform {
 
     @PluggableDependency(PlatformGenerator.class)
     @InjectedBy(PlatformGenerator.class)
+    @DelegateTo("initClassLowLevel")
     public static native void initClass(PlatformClass cls);
 
+    @Unmanaged
+    private static void initClassLowLevel(RuntimeClass cls) {
+        if (cls.init != null) {
+            cls.init.run();
+        }
+    }
+
     @InjectedBy(PlatformGenerator.class)
     @PluggableDependency(PlatformGenerator.class)
     public static native PlatformClass classFromResource(ClassResource resource);
diff --git a/platform/src/main/java/org/teavm/platform/PlatformClassMetadata.java b/platform/src/main/java/org/teavm/platform/PlatformClassMetadata.java
index bbca2938d..de7c1d193 100644
--- a/platform/src/main/java/org/teavm/platform/PlatformClassMetadata.java
+++ b/platform/src/main/java/org/teavm/platform/PlatformClassMetadata.java
@@ -15,17 +15,20 @@
  */
 package org.teavm.platform;
 
+import org.teavm.interop.Unmanaged;
 import org.teavm.jso.JSObject;
 import org.teavm.jso.JSProperty;
 
 public interface PlatformClassMetadata extends JSObject {
     @JSProperty("item")
+    @Unmanaged
     PlatformClass getArrayItem();
 
     @JSProperty
     PlatformSequence<PlatformClass> getSupertypes();
 
     @JSProperty
+    @Unmanaged
     PlatformClass getSuperclass();
 
     @JSProperty