Implement development server

core/src/main/java/org/teavm/backend/javascript/JavaScriptTarget.java

@@ -324,6 +324,7 @@ public class JavaScriptTarget implements TeaVMTarget, TeaVMJavaScriptHost {
         RuntimeRenderer runtimeRenderer = new RuntimeRenderer(classes, naming, sourceWriter);
         renderer.setProperties(controller.getProperties());
         renderer.setMinifying(minifying);
+        renderer.setProgressConsumer(controller::reportProgress);
         if (debugEmitter != null) {
             for (String className : classes.getClassNames()) {
                 ClassHolder cls = classes.get(className);
@@ -352,7 +353,9 @@ public class JavaScriptTarget implements TeaVMTarget, TeaVMJavaScriptHost {
 
             renderer.prepare(clsNodes);
             runtimeRenderer.renderRuntime();
-            renderer.render(clsNodes);
+            if (!renderer.render(clsNodes)) {
+                return;
+            }
             renderer.renderStringPool();
             renderer.renderStringConstants();
             renderer.renderCompatibilityStubs();

core/src/main/java/org/teavm/backend/javascript/codegen/DefaultNamingStrategy.java

@@ -52,20 +52,20 @@ public class DefaultNamingStrategy implements NamingStrategy {
     }
 
     @Override
-    public String getFullNameFor(MethodReference method) throws NamingException {
+    public String getFullNameFor(MethodReference method) {
         return getFullNameFor(method, 'M');
     }
 
     @Override
-    public String getNameForInit(MethodReference method) throws NamingException {
+    public String getNameForInit(MethodReference method) {
         return getFullNameFor(method, 'I');
     }
 
-    private String getFullNameFor(MethodReference method, char classifier) throws NamingException {
+    private String getFullNameFor(MethodReference method, char classifier) {
         MethodReference originalMethod = method;
         method = getRealMethod(method);
         if (method == null) {
-            throw new NamingException("Can't provide name for method as it was not found: " + originalMethod);
+            method = originalMethod;
         }
 
         MethodReference resolvedMethod = method;
@@ -86,7 +86,7 @@ public class DefaultNamingStrategy implements NamingStrategy {
     }
 
     @Override
-    public String getFullNameFor(FieldReference field) throws NamingException {
+    public String getFullNameFor(FieldReference field) {
         String realCls = getRealFieldOwner(field.getClassName(), field.getFieldName());
         if (!realCls.equals(field.getClassName())) {
             String alias = getNameFor(new FieldReference(realCls, field.getFieldName()));
@@ -99,12 +99,12 @@ public class DefaultNamingStrategy implements NamingStrategy {
     }
 
     @Override
-    public String getNameForFunction(String name) throws NamingException {
+    public String getNameForFunction(String name) {
         return functionAliases.computeIfAbsent(name, key -> aliasProvider.getFunctionAlias(key));
     }
 
     @Override
-    public String getNameForClassInit(String className) throws NamingException {
+    public String getNameForClassInit(String className) {
         return classInitAliases.computeIfAbsent(className, key -> aliasProvider.getClassInitAlias(key));
     }
 
@@ -131,17 +131,16 @@ public class DefaultNamingStrategy implements NamingStrategy {
         String initialCls = cls;
         while (!fieldExists(cls, field)) {
             ClassReader clsHolder = classSource.get(cls);
-            cls = clsHolder.getParent();
+            if (clsHolder == null || clsHolder.getParent() == null) {
-            if (cls == null) {
+                return initialCls;
-                throw new NamingException("Can't provide name for field as the field not found: "
-                        + initialCls + "." + field);
             }
+            cls = clsHolder.getParent();
         }
         return cls;
     }
 
     private boolean fieldExists(String cls, String field) {
         ClassReader classHolder = classSource.get(cls);
-        return classHolder.getField(field) != null;
+        return classHolder != null && classHolder.getField(field) != null;
     }
 }

core/src/main/java/org/teavm/backend/javascript/codegen/NamingException.java

@@ -1,28 +0,0 @@
-/*
- *  Copyright 2016 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.backend.javascript.codegen;
-
-public class NamingException extends RuntimeException {
-    private static final long serialVersionUID = 3472322553091962348L;
-
-    public NamingException() {
-        super();
-    }
-
-    public NamingException(String message) {
-        super(message);
-    }
-}

core/src/main/java/org/teavm/backend/javascript/codegen/NamingStrategy.java

@@ -20,19 +20,19 @@ import org.teavm.model.MethodDescriptor;
 import org.teavm.model.MethodReference;
 
 public interface NamingStrategy {
-    String getNameFor(String cls) throws NamingException;
+    String getNameFor(String cls);
 
-    String getNameFor(MethodDescriptor method) throws NamingException;
+    String getNameFor(MethodDescriptor method);
 
-    String getNameForInit(MethodReference method) throws NamingException;
+    String getNameForInit(MethodReference method);
 
-    String getFullNameFor(MethodReference method) throws NamingException;
+    String getFullNameFor(MethodReference method);
 
-    String getNameFor(FieldReference field) throws NamingException;
+    String getNameFor(FieldReference field);
 
-    String getFullNameFor(FieldReference method) throws NamingException;
+    String getFullNameFor(FieldReference method);
 
-    String getNameForFunction(String name) throws NamingException;
+    String getNameForFunction(String name);
 
-    String getNameForClassInit(String className) throws NamingException;
+    String getNameForClassInit(String className);
 }

core/src/main/java/org/teavm/backend/javascript/codegen/SourceWriter.java

@@ -98,45 +98,43 @@ public class SourceWriter implements Appendable, LocationProvider {
         innerWriter.append(csq, start, end);
     }
 
-    public SourceWriter appendClass(String cls) throws NamingException, IOException {
+    public SourceWriter appendClass(String cls) throws IOException {
         return append(naming.getNameFor(cls));
     }
 
-    public SourceWriter appendClass(Class<?> cls) throws NamingException, IOException {
+    public SourceWriter appendClass(Class<?> cls) throws IOException {
         return append(naming.getNameFor(cls.getName()));
     }
 
-    public SourceWriter appendField(FieldReference field) throws NamingException, IOException {
+    public SourceWriter appendField(FieldReference field) throws IOException {
         return append(naming.getNameFor(field));
     }
 
-    public SourceWriter appendStaticField(FieldReference field) throws NamingException, IOException {
+    public SourceWriter appendStaticField(FieldReference field) throws IOException {
         return append(naming.getFullNameFor(field));
     }
 
-    public SourceWriter appendMethod(MethodDescriptor method) throws NamingException, IOException {
+    public SourceWriter appendMethod(MethodDescriptor method) throws IOException {
         return append(naming.getNameFor(method));
     }
 
-    public SourceWriter appendMethod(String name, Class<?>... params) throws NamingException, IOException {
+    public SourceWriter appendMethod(String name, Class<?>... params) throws IOException {
         return append(naming.getNameFor(new MethodDescriptor(name, params)));
     }
 
-    public SourceWriter appendMethodBody(MethodReference method) throws NamingException, IOException {
+    public SourceWriter appendMethodBody(MethodReference method) throws IOException {
         return append(naming.getFullNameFor(method));
     }
 
-    public SourceWriter appendMethodBody(String className, String name, ValueType... params)
+    public SourceWriter appendMethodBody(String className, String name, ValueType... params) throws IOException {
-            throws NamingException, IOException {
         return append(naming.getFullNameFor(new MethodReference(className, new MethodDescriptor(name, params))));
     }
 
-    public SourceWriter appendMethodBody(Class<?> cls, String name, Class<?>... params)
+    public SourceWriter appendMethodBody(Class<?> cls, String name, Class<?>... params) throws IOException {
-            throws NamingException, IOException {
         return append(naming.getFullNameFor(new MethodReference(cls, name, params)));
     }
 
-    public SourceWriter appendFunction(String name) throws NamingException, IOException {
+    public SourceWriter appendFunction(String name) throws IOException {
         return append(naming.getNameForFunction(name));
     }
 

core/src/main/java/org/teavm/backend/javascript/rendering/Renderer.java

@@ -27,6 +27,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Properties;
 import java.util.Set;
+import java.util.function.IntFunction;
 import java.util.stream.Collectors;
 import org.teavm.ast.AsyncMethodNode;
 import org.teavm.ast.AsyncMethodPart;
@@ -37,7 +38,6 @@ import org.teavm.ast.MethodNodeVisitor;
 import org.teavm.ast.NativeMethodNode;
 import org.teavm.ast.RegularMethodNode;
 import org.teavm.ast.VariableNode;
-import org.teavm.backend.javascript.codegen.NamingException;
 import org.teavm.backend.javascript.codegen.NamingOrderer;
 import org.teavm.backend.javascript.codegen.NamingStrategy;
 import org.teavm.backend.javascript.codegen.SourceWriter;
@@ -57,6 +57,7 @@ import org.teavm.model.MethodReader;
 import org.teavm.model.MethodReference;
 import org.teavm.model.ValueType;
 import org.teavm.vm.RenderingException;
+import org.teavm.vm.TeaVMProgressFeedback;
 
 public class Renderer implements RenderingManager {
     private final NamingStrategy naming;
@@ -72,6 +73,7 @@ public class Renderer implements RenderingManager {
     private final Diagnostics diagnostics;
     private RenderingContext context;
     private List<PostponedFieldInitializer> postponedFieldInitializers = new ArrayList<>();
+    private IntFunction<TeaVMProgressFeedback> progressConsumer = p -> TeaVMProgressFeedback.CONTINUE;
 
     private ObjectIntMap<String> sizeByClass = new ObjectIntHashMap<>();
     private int stringPoolSize;
@@ -161,6 +163,10 @@ public class Renderer implements RenderingManager {
         this.debugEmitter = debugEmitter;
     }
 
+    public void setProgressConsumer(IntFunction<TeaVMProgressFeedback> progressConsumer) {
+        this.progressConsumer = progressConsumer;
+    }
+
     public void setProperties(Properties properties) {
         this.properties.clear();
         this.properties.putAll(properties);
@@ -265,7 +271,7 @@ public class Renderer implements RenderingManager {
         }
     }
 
-    public void render(List<ClassNode> classes) throws RenderingException {
+    public boolean render(List<ClassNode> classes) throws RenderingException {
         if (minifying) {
             try {
                 renderRuntimeAliases();
@@ -273,13 +279,18 @@ public class Renderer implements RenderingManager {
                 throw new RenderingException(e);
             }
         }
+        int index = 0;
         for (ClassNode cls : classes) {
             int start = writer.getOffset();
             renderDeclaration(cls);
             renderMethodBodies(cls);
             appendClassSize(cls.getName(), writer.getOffset() - start);
+            if (progressConsumer.apply(1000 * ++index / classes.size()) == TeaVMProgressFeedback.CANCEL) {
+                return false;
+            }
         }
         renderClassMetadata(classes);
+        return true;
     }
 
     private void renderDeclaration(ClassNode cls) throws RenderingException {
@@ -337,8 +348,6 @@ public class Renderer implements RenderingManager {
                 writer.append("var ").appendStaticField(fieldRef).ws().append("=").ws()
                         .append(context.constantToString(value)).append(";").softNewLine();
             }
-        } catch (NamingException e) {
-            throw new RenderingException("Error rendering class " + cls.getName() + ". See cause for details", e);
         } catch (IOException e) {
             throw new RenderingException("IO error occurred", e);
         }
@@ -366,8 +375,6 @@ public class Renderer implements RenderingManager {
             for (MethodNode method : cls.getMethods()) {
                 renderBody(method);
             }
-        } catch (NamingException e) {
-            throw new RenderingException("Error rendering class " + cls.getName() + ". See a cause for details", e);
         } catch (IOException e) {
             throw new RenderingException("IO error occurred", e);
         }
@@ -508,8 +515,6 @@ public class Renderer implements RenderingManager {
                 renderVirtualDeclarations(virtualMethods);
             }
             writer.append("]);").newLine();
-        } catch (NamingException e) {
-            throw new RenderingException("Error rendering class metadata. See a cause for details", e);
         } catch (IOException e) {
             throw new RenderingException("IO error occurred", e);
         }
@@ -688,7 +693,7 @@ public class Renderer implements RenderingManager {
         return minifying ? RenderingUtil.indexToId(index) : "var_" + index;
     }
 
-    private void renderVirtualDeclarations(Collection<MethodReference> methods) throws NamingException, IOException {
+    private void renderVirtualDeclarations(Collection<MethodReference> methods) throws IOException {
         if (methods.stream().noneMatch(this::isVirtual)) {
             writer.append('0');
             return;

core/src/main/java/org/teavm/backend/javascript/rendering/RuntimeRenderer.java

@@ -23,7 +23,6 @@ import java.nio.charset.StandardCharsets;
 import org.mozilla.javascript.CompilerEnvirons;
 import org.mozilla.javascript.Context;
 import org.mozilla.javascript.ast.AstRoot;
-import org.teavm.backend.javascript.codegen.NamingException;
 import org.teavm.backend.javascript.codegen.NamingStrategy;
 import org.teavm.backend.javascript.codegen.SourceWriter;
 import org.teavm.model.ClassReader;
@@ -73,8 +72,6 @@ public class RuntimeRenderer {
             renderRuntimeCreateException();
             renderCreateStackTraceElement();
             renderSetStackTrace();
-        } catch (NamingException e) {
-            throw new RenderingException("Error rendering runtime methods. See a cause for details", e);
         } catch (IOException e) {
             throw new RenderingException("IO error", e);
         }

core/src/main/java/org/teavm/cache/AlwaysFreshCacheStatus.java

@@ -1,35 +0,0 @@
-/*
- *  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.cache;
-
-import org.teavm.model.MethodReference;
-
-public class AlwaysFreshCacheStatus implements CacheStatus {
-    public static final AlwaysFreshCacheStatus INSTANCE = new AlwaysFreshCacheStatus();
-
-    private AlwaysFreshCacheStatus() {
-    }
-
-    @Override
-    public boolean isStaleClass(String className) {
-        return false;
-    }
-
-    @Override
-    public boolean isStaleMethod(MethodReference method) {
-        return false;
-    }
-}

core/src/main/java/org/teavm/cache/MemoryCachedClassReaderSource.java

@@ -0,0 +1,65 @@
+/*
+ *  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.cache;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import org.teavm.model.ClassReader;
+import org.teavm.model.ClassReaderSource;
+import org.teavm.model.MethodReference;
+
+public class MemoryCachedClassReaderSource implements ClassReaderSource, CacheStatus {
+    private ClassReaderSource underlyingSource;
+    private final Map<String, Optional<ClassReader>> cache = new HashMap<>();
+    private final Set<String> freshClasses = new HashSet<>();
+
+    public void setUnderlyingSource(ClassReaderSource underlyingSource) {
+        this.underlyingSource = underlyingSource;
+    }
+
+    @Override
+    public boolean isStaleClass(String className) {
+        return !freshClasses.contains(className);
+    }
+
+    @Override
+    public boolean isStaleMethod(MethodReference method) {
+        return isStaleClass(method.getClassName());
+    }
+
+    @Override
+    public ClassReader get(String name) {
+        return cache.computeIfAbsent(name, key -> {
+            if (underlyingSource == null) {
+                return Optional.empty();
+            }
+            return Optional.ofNullable(underlyingSource.get(key));
+        }).orElse(null);
+    }
+
+    public void commit() {
+        freshClasses.addAll(cache.keySet());
+    }
+
+    public void evict(Collection<? extends String> classes) {
+        cache.keySet().removeAll(classes);
+        freshClasses.removeAll(classes);
+    }
+}

core/src/main/java/org/teavm/dependency/DependencyAnalyzer.java

@@ -648,7 +648,6 @@ public abstract class DependencyAnalyzer implements DependencyInfo {
         if (interrupted) {
             return;
         }
-        int index = 0;
         while (!deferredTasks.isEmpty() || !tasks.isEmpty() || !pendingTransitions.isEmpty()) {
             while (true) {
                 processNodeToNodeTransitionQueue();
@@ -658,12 +657,9 @@ public abstract class DependencyAnalyzer implements DependencyInfo {
                 while (!tasks.isEmpty()) {
                     tasks.remove().run();
                 }
-                if (++index == 100) {
                 if (interruptor != null && !interruptor.shouldContinue()) {
                     interrupted = true;
-                        break;
+                    return;
-                    }
-                    index = 0;
                 }
             }
 

core/src/main/java/org/teavm/model/util/MissingItemsProcessor.java

@@ -243,6 +243,7 @@ public class MissingItemsProcessor {
         public void visit(CastInstruction insn) {
             checkClass(insn.getLocation(), insn.getTargetType());
         }
+
         @Override
         public void visit(ClassConstantInstruction insn) {
             checkClass(insn.getLocation(), insn.getConstant());

core/src/main/java/org/teavm/vm/MemoryBuildTarget.java

@@ -0,0 +1,53 @@
+/*
+ *  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.vm;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Set;
+
+public class MemoryBuildTarget implements BuildTarget {
+    private Map<String, ByteArrayOutputStream> data = new LinkedHashMap<>();
+    private Set<? extends String> names = Collections.unmodifiableSet(data.keySet());
+
+    public Set<? extends String> getNames() {
+        return names;
+    }
+
+    public byte[] getContent(String name) {
+        ByteArrayOutputStream stream = data.get(name);
+        return stream != null ? stream.toByteArray() : null;
+    }
+
+    public void clear() {
+        data.clear();
+    }
+
+    @Override
+    public OutputStream createResource(String fileName) throws IOException {
+        ByteArrayOutputStream stream = new ByteArrayOutputStream();
+        data.put(fileName, stream);
+        return stream;
+    }
+
+    public OutputStream appendToResource(String fileName) {
+        return data.computeIfAbsent(fileName, k -> new ByteArrayOutputStream());
+    }
+}

core/src/main/java/org/teavm/vm/TeaVM.java

@@ -140,6 +140,7 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
     private AnnotationAwareCacheStatus cacheStatus;
     private ProgramDependencyExtractor programDependencyExtractor = new ProgramDependencyExtractor();
     private List<Predicate<MethodReference>> additionalVirtualMethods = new ArrayList<>();
+    private int lastKnownClasses;
 
     TeaVM(TeaVMBuilder builder) {
         target = builder.target;
@@ -336,6 +337,10 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
         return writtenClasses;
     }
 
+    public void setLastKnownClasses(int lastKnownClasses) {
+        this.lastKnownClasses = lastKnownClasses;
+    }
+
     /**
      * <p>Does actual build. Call this method after TeaVM is fully configured and all entry points
      * are specified. This method may fail if there are items (classes, methods and fields)
@@ -351,13 +356,16 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
         target.setController(targetController);
 
         // Check dependencies
-        reportPhase(TeaVMPhase.DEPENDENCY_ANALYSIS, 1);
+        reportPhase(TeaVMPhase.DEPENDENCY_ANALYSIS, lastKnownClasses > 0 ? lastKnownClasses : 1);
         if (wasCancelled()) {
             return;
         }
 
         dependencyAnalyzer.setAsyncSupported(target.isAsyncSupported());
-        dependencyAnalyzer.setInterruptor(() -> progressListener.progressReached(0) == TeaVMProgressFeedback.CONTINUE);
+        dependencyAnalyzer.setInterruptor(() -> {
+            int progress = lastKnownClasses > 0 ? dependencyAnalyzer.getReachableClasses().size() : 0;
+            return progressListener.progressReached(progress) == TeaVMProgressFeedback.CONTINUE;
+        });
         target.contributeDependencies(dependencyAnalyzer);
         dependencyAnalyzer.processDependencies();
         if (wasCancelled() || !diagnostics.getSevereProblems().isEmpty()) {
@@ -368,7 +376,6 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
         cacheStatus.addSynthesizedClasses(dependencyAnalyzer::isSynthesizedClass);
 
         // Link
-        reportPhase(TeaVMPhase.LINKING, 1);
         if (wasCancelled()) {
             return;
         }
@@ -379,28 +386,36 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
         }
 
         // Optimize and allocate registers
-        reportPhase(TeaVMPhase.OPTIMIZATION, 1);
+        int maxOptimizationProgress = classSet.getClassNames().size();
+        if (optimizationLevel == TeaVMOptimizationLevel.ADVANCED) {
+            maxOptimizationProgress *= 2;
+        } else if (optimizationLevel == TeaVMOptimizationLevel.FULL) {
+            maxOptimizationProgress *= 3;
+        }
+        reportPhase(TeaVMPhase.OPTIMIZATION, maxOptimizationProgress);
 
+        int progress = 0;
         if (optimizationLevel != TeaVMOptimizationLevel.SIMPLE) {
-            devirtualize(classSet, dependencyAnalyzer);
+            progress = devirtualize(progress, classSet, dependencyAnalyzer);
             if (wasCancelled()) {
                 return;
             }
         }
 
         dependencyAnalyzer.cleanup();
-        inline(classSet, dependencyAnalyzer);
+        progress = inline(progress, classSet, dependencyAnalyzer);
         if (wasCancelled()) {
             return;
         }
 
-        optimize(classSet);
+        optimize(progress, classSet);
         if (wasCancelled()) {
             return;
         }
 
         // Render
         try {
+            reportPhase(TeaVMPhase.RENDERING, 1000);
             target.emit(classSet, buildTarget, outputName);
         } catch (IOException e) {
             throw new RuntimeException("Error generating output files", e);
@@ -442,28 +457,31 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
         }
     }
 
-    private void devirtualize(ListableClassHolderSource classes, DependencyInfo dependency) {
+    private int devirtualize(int progress, ListableClassHolderSource classes, DependencyInfo dependency) {
         if (wasCancelled()) {
-            return;
+            return progress;
         }
         Devirtualization devirtualization = new Devirtualization(dependency, classes);
+        int index = 0;
         for (String className : classes.getClassNames()) {
             ClassHolder cls = classes.get(className);
-            for (final MethodHolder method : cls.getMethods()) {
+            for (MethodHolder method : cls.getMethods()) {
                 if (method.getProgram() != null) {
                     devirtualization.apply(method);
                 }
             }
+            progressListener.progressReached(++index);
             if (wasCancelled()) {
-                return;
+                break;
             }
         }
         virtualMethods = devirtualization.getVirtualMethods();
+        return progress;
     }
 
-    private void inline(ListableClassHolderSource classes, DependencyInfo dependencyInfo) {
+    private int inline(int progress, ListableClassHolderSource classes, DependencyInfo dependencyInfo) {
         if (optimizationLevel != TeaVMOptimizationLevel.FULL) {
-            return;
+            return progress;
         }
 
         Map<MethodReference, Program> inlinedPrograms = new HashMap<>();
@@ -479,8 +497,9 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
                     inlinedPrograms.put(method.getReference(), program);
                 }
             }
+            progressListener.progressReached(++progress);
             if (wasCancelled()) {
-                return;
+                break;
             }
         }
 
@@ -492,18 +511,22 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
                 }
             }
         }
+
+        return progress;
     }
 
-    private void optimize(ListableClassHolderSource classSource) {
+    private int optimize(int progress, ListableClassHolderSource classSource) {
         for (String className : classSource.getClassNames()) {
             ClassHolder cls = classSource.get(className);
             for (MethodHolder method : cls.getMethods()) {
                 processMethod(method, classSource);
             }
+            progressListener.progressReached(++progress);
             if (wasCancelled()) {
-                return;
+                break;
             }
         }
+        return progress;
     }
 
     private void processMethod(MethodHolder method, ListableClassReaderSource classSource) {
@@ -700,5 +723,10 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
         public boolean isVirtual(MethodReference method) {
             return virtualMethods == null || virtualMethods.contains(method);
         }
+
+        @Override
+        public TeaVMProgressFeedback reportProgress(int progres) {
+            return progressListener.progressReached(progres);
+        }
     };
 }

core/src/main/java/org/teavm/vm/TeaVMPhase.java

@@ -19,6 +19,5 @@ public enum TeaVMPhase {
     DEPENDENCY_ANALYSIS,
     LINKING,
     OPTIMIZATION,
-    DECOMPILATION,
     RENDERING
 }

core/src/main/java/org/teavm/vm/TeaVMTargetController.java

@@ -49,4 +49,6 @@ public interface TeaVMTargetController {
     Set<? extends String> getPreservedClasses();
 
     boolean isVirtual(MethodReference method);
+
+    TeaVMProgressFeedback reportProgress(int progress);
 }

pom.xml

@@ -66,7 +66,7 @@
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <sonatypeOssDistMgmtSnapshotsUrl>https://oss.sonatype.org/content/repositories/snapshots/</sonatypeOssDistMgmtSnapshotsUrl>
     <html4j.version>1.5</html4j.version>
-    <jetty.version>9.2.1.v20140609</jetty.version>
+    <jetty.version>9.4.14.v20181114</jetty.version>
     <slf4j.version>1.7.7</slf4j.version>
     <jackson.version>2.6.2</jackson.version>
     <idea.version>2017.3.5</idea.version>
@@ -93,6 +93,7 @@
     <module>tools/maven</module>
     <module>tools/chrome-rdp</module>
     <module>tools/junit</module>
+    <module>tools/devserver</module>
     <module>tests</module>
     <module>extras-slf4j</module>
     <module>metaprogramming/impl</module>

samples/benchmark/src/main/java/org/teavm/samples/benchmark/teavm/BenchmarkStarter.java

@@ -44,6 +44,7 @@ public final class BenchmarkStarter {
     private static double timeSpentCalculating;
     private static double totalTime;
 
+
     private BenchmarkStarter() {
     }
 

tools/chrome-rdp/pom.xml

@@ -50,15 +50,11 @@
       <groupId>javax.websocket</groupId>
       <artifactId>javax.websocket-api</artifactId>
     </dependency>
+
     <dependency>
-      <groupId>org.codehaus.jackson</groupId>
+      <groupId>com.fasterxml.jackson.core</groupId>
-      <artifactId>jackson-core-asl</artifactId>
+      <artifactId>jackson-databind</artifactId>
-      <version>1.9.13</version>
+      <optional>true</optional>
-    </dependency>
-    <dependency>
-      <groupId>org.codehaus.jackson</groupId>
-      <artifactId>jackson-mapper-asl</artifactId>
-      <version>1.9.13</version>
     </dependency>
   </dependencies>
 

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/ChromeRDPDebugger.java

@@ -15,6 +15,8 @@
  */
 package org.teavm.chromerdp;
 
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -29,8 +31,6 @@ import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
-import org.codehaus.jackson.JsonNode;
-import org.codehaus.jackson.map.ObjectMapper;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.teavm.chromerdp.data.CallArgumentDTO;
@@ -149,7 +149,7 @@ public class ChromeRDPDebugger implements JavaScriptDebugger, ChromeRDPExchangeC
                         future.completeExceptionally(e);
                     }
                 } else {
-                    Message message = mapper.reader(Message.class).readValue(messageText);
+                    Message message = mapper.readerFor(Message.class).readValue(messageText);
                     if (message.getMethod() == null) {
                         return;
                     }
@@ -404,7 +404,7 @@ public class ChromeRDPDebugger implements JavaScriptDebugger, ChromeRDPExchangeC
 
         CallFunctionResponse response = callMethod("Runtime.callFunctionOn", CallFunctionResponse.class, params);
         RemoteObjectDTO result = response != null ? response.getResult() : null;
-        return result.getValue() != null ? result.getValue().getTextValue() : null;
+        return result.getValue() != null ? result.getValue().textValue() : null;
     }
 
     String getRepresentation(String objectId) {
@@ -417,7 +417,7 @@ public class ChromeRDPDebugger implements JavaScriptDebugger, ChromeRDPExchangeC
 
         CallFunctionResponse response = callMethod("Runtime.callFunctionOn", CallFunctionResponse.class, params);
         RemoteObjectDTO result = response != null ? response.getResult() : null;
-        return result.getValue() != null ? result.getValue().getTextValue() : null;
+        return result.getValue() != null ? result.getValue().textValue() : null;
     }
 
     private List<RDPLocalVariable> parseProperties(PropertyDescriptorDTO[] properties) {
@@ -452,7 +452,7 @@ public class ChromeRDPDebugger implements JavaScriptDebugger, ChromeRDPExchangeC
     }
 
     private <T> T parseJson(Class<T> type, JsonNode node) throws IOException {
-        return mapper.reader(type).readValue(node);
+        return mapper.readerFor(type).readValue(node);
     }
 
     private void sendMessage(Message message) {
@@ -516,7 +516,7 @@ public class ChromeRDPDebugger implements JavaScriptDebugger, ChromeRDPExchangeC
             if (node == null) {
                 out.complete(null);
             } else {
-                R response = returnType != void.class ? mapper.reader(returnType).readValue(node) : null;
+                R response = returnType != void.class ? mapper.readerFor(returnType).readValue(node) : null;
                 out.complete(response);
             }
         });

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/ChromeRDPServer.java

@@ -15,7 +15,10 @@
  */
 package org.teavm.chromerdp;
 
-import java.util.*;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 import javax.websocket.Decoder;
 import javax.websocket.Encoder;
 import javax.websocket.Extension;
@@ -57,9 +60,8 @@ public class ChromeRDPServer {
         context.setContextPath("/");
         server.setHandler(context);
 
-        ServerContainer wscontainer = WebSocketServerContainerInitializer.configureContext(context);
-
         try {
+            ServerContainer wscontainer = WebSocketServerContainerInitializer.configureContext(context);
             wscontainer.addEndpoint(new RPDEndpointConfig());
             server.start();
             server.join();

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/data/CallArgumentDTO.java

@@ -15,8 +15,8 @@
  */
 package org.teavm.chromerdp.data;
 
-import org.codehaus.jackson.JsonNode;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.databind.JsonNode;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class CallArgumentDTO {

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/data/CallFrameDTO.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.data;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class CallFrameDTO {

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/data/LocationDTO.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.data;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class LocationDTO {

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/data/Message.java

@@ -15,8 +15,8 @@
  */
 package org.teavm.chromerdp.data;
 
-import org.codehaus.jackson.JsonNode;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.databind.JsonNode;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class Message {

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/data/PropertyDescriptorDTO.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.data;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class PropertyDescriptorDTO {

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/data/RemoteObjectDTO.java

@@ -15,8 +15,8 @@
  */
 package org.teavm.chromerdp.data;
 
-import org.codehaus.jackson.JsonNode;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.databind.JsonNode;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class RemoteObjectDTO {

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/data/Response.java

@@ -15,8 +15,8 @@
  */
 package org.teavm.chromerdp.data;
 
-import org.codehaus.jackson.JsonNode;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.databind.JsonNode;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class Response {

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/data/ScopeDTO.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.data;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class ScopeDTO {

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/messages/CallFunctionCommand.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.messages;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import org.teavm.chromerdp.data.CallArgumentDTO;
 
 @JsonIgnoreProperties(ignoreUnknown = true)

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/messages/CallFunctionResponse.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.messages;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import org.teavm.chromerdp.data.RemoteObjectDTO;
 
 @JsonIgnoreProperties(ignoreUnknown = true)

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/messages/CompileScriptCommand.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.messages;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class CompileScriptCommand {

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/messages/CompileScriptResponse.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.messages;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class CompileScriptResponse {

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/messages/ContinueToLocationCommand.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.messages;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import org.teavm.chromerdp.data.LocationDTO;
 
 @JsonIgnoreProperties(ignoreUnknown = true)

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/messages/GetPropertiesCommand.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.messages;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class GetPropertiesCommand {

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/messages/GetPropertiesResponse.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.messages;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import org.teavm.chromerdp.data.PropertyDescriptorDTO;
 
 @JsonIgnoreProperties(ignoreUnknown = true)

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/messages/RemoveBreakpointCommand.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.messages;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class RemoveBreakpointCommand {

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/messages/RunScriptCommand.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.messages;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class RunScriptCommand {

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/messages/ScriptParsedNotification.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.messages;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class ScriptParsedNotification {

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/messages/SetBreakpointCommand.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.messages;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import org.teavm.chromerdp.data.LocationDTO;
 
 @JsonIgnoreProperties(ignoreUnknown = true)

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/messages/SetBreakpointResponse.java

@@ -15,7 +15,7 @@
  */
 package org.teavm.chromerdp.messages;
 
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import org.teavm.chromerdp.data.LocationDTO;
 
 @JsonIgnoreProperties(ignoreUnknown = true)

tools/chrome-rdp/src/main/java/org/teavm/chromerdp/messages/SuspendedNotification.java

@@ -15,9 +15,9 @@
  */
 package org.teavm.chromerdp.messages;
 
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import com.fasterxml.jackson.databind.JsonNode;
 import java.util.List;
-import org.codehaus.jackson.JsonNode;
-import org.codehaus.jackson.annotate.JsonIgnoreProperties;
 import org.teavm.chromerdp.data.CallFrameDTO;
 
 @JsonIgnoreProperties(ignoreUnknown = true)

tools/cli/pom.xml

@@ -51,6 +51,11 @@
       <version>${project.version}</version>
       <scope>runtime</scope>
     </dependency>
+    <dependency>
+      <groupId>org.teavm</groupId>
+      <artifactId>teavm-devserver</artifactId>
+      <version>${project.version}</version>
+    </dependency>
     <dependency>
       <groupId>org.teavm</groupId>
       <artifactId>teavm-jso-impl</artifactId>

tools/cli/src/main/java/org/teavm/cli/TeaVMDevServerRunner.java

@@ -0,0 +1,163 @@
+/*
+ *  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.cli;
+
+import java.util.Arrays;
+import org.apache.commons.cli.CommandLine;
+import org.apache.commons.cli.CommandLineParser;
+import org.apache.commons.cli.HelpFormatter;
+import org.apache.commons.cli.OptionBuilder;
+import org.apache.commons.cli.Options;
+import org.apache.commons.cli.ParseException;
+import org.apache.commons.cli.PosixParser;
+import org.teavm.devserver.DevServer;
+import org.teavm.tooling.ConsoleTeaVMToolLog;
+
+public final class TeaVMDevServerRunner {
+    private static Options options = new Options();
+    private ConsoleTeaVMToolLog log = new ConsoleTeaVMToolLog(false);
+    private DevServer devServer;
+    private CommandLine commandLine;
+
+    static {
+        setupOptions();
+    }
+
+    @SuppressWarnings("static-access")
+    private static void setupOptions() {
+        options.addOption(OptionBuilder
+                .withArgName("directory")
+                .hasArg()
+                .withDescription("a directory, relative to server's root, which serves generated files")
+                .withLongOpt("targetdir")
+                .create('d'));
+        options.addOption(OptionBuilder
+                .withArgName("file")
+                .hasArg()
+                .withDescription("a file where to put decompiled classes (classes.js by default)")
+                .withLongOpt("targetfile")
+                .create('f'));
+        options.addOption(OptionBuilder
+                .withArgName("classpath")
+                .hasArg()
+                .withDescription("classpath element (either directory or jar file)")
+                .withLongOpt("classpath")
+                .create('p'));
+        options.addOption(OptionBuilder
+                .withArgName("sourcepath")
+                .hasArg()
+                .withDescription("source path (either directory or jar file which contains source code)")
+                .withLongOpt("sourcepath")
+                .create('s'));
+        options.addOption(OptionBuilder
+                .withArgName("number")
+                .hasArg()
+                .withDescription("port (default is 9090)")
+                .create("port"));
+        options.addOption(OptionBuilder
+                .withDescription("display indicator on web page")
+                .create("indicator"));
+        options.addOption(OptionBuilder
+                .withDescription("display more messages on server log")
+                .withLongOpt("verbose")
+                .create('v'));
+    }
+
+    private TeaVMDevServerRunner(CommandLine commandLine) {
+        this.commandLine = commandLine;
+        devServer = new DevServer();
+    }
+
+    public static void main(String[] args) {
+        if (args.length == 0) {
+            printUsage();
+            return;
+        }
+        CommandLineParser parser = new PosixParser();
+        CommandLine commandLine;
+        try {
+            commandLine = parser.parse(options, args);
+        } catch (ParseException e) {
+            printUsage();
+            return;
+        }
+
+        TeaVMDevServerRunner runner = new TeaVMDevServerRunner(commandLine);
+        runner.parseArguments();
+        runner.setUp();
+        runner.runAll();
+    }
+
+    private void parseArguments() {
+        parseClassPathOptions();
+        parseSourcePathOptions();
+        parseOutputOptions();
+
+        devServer.setIndicator(commandLine.hasOption("indicator"));
+        if (commandLine.hasOption("port")) {
+            try {
+                devServer.setPort(Integer.parseInt(commandLine.getOptionValue("port")));
+            } catch (NumberFormatException e) {
+                System.err.println("port must be numeric");
+                printUsage();
+            }
+        }
+
+        String[] args = commandLine.getArgs();
+        if (args.length != 1) {
+            System.err.println("Unexpected arguments");
+            printUsage();
+        } else if (args.length == 1) {
+            devServer.setMainClass(args[0]);
+        }
+    }
+
+    private void parseOutputOptions() {
+        if (commandLine.hasOption("d")) {
+            devServer.setPathToFile(commandLine.getOptionValue("d"));
+        }
+        if (commandLine.hasOption("f")) {
+            devServer.setFileName(commandLine.getOptionValue("f"));
+        }
+    }
+
+    private void parseClassPathOptions() {
+        if (commandLine.hasOption('p')) {
+            devServer.setClassPath(commandLine.getOptionValues('p'));
+        }
+    }
+
+    private void parseSourcePathOptions() {
+        if (commandLine.hasOption('s')) {
+            devServer.getSourcePath().addAll(Arrays.asList(commandLine.getOptionValues('s')));
+        }
+    }
+
+    private void setUp() {
+        devServer.setLog(log);
+    }
+
+    private void runAll() {
+        devServer.start();
+    }
+
+    private static void printUsage() {
+        HelpFormatter formatter = new HelpFormatter();
+        formatter.printHelp("java " + TeaVMDevServerRunner.class.getName() + " [OPTIONS] [qualified.main.Class]",
+                options);
+        System.exit(-1);
+    }
+}

tools/cli/src/main/java/org/teavm/cli/TeaVMRunner.java

@@ -20,24 +20,7 @@ import java.io.IOException;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLClassLoader;
-import java.nio.file.FileSystems;
-import java.nio.file.FileVisitResult;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.nio.file.Paths;
-import java.nio.file.SimpleFileVisitor;
-import java.nio.file.StandardWatchEventKinds;
-import java.nio.file.WatchEvent;
-import java.nio.file.WatchKey;
-import java.nio.file.WatchService;
-import java.nio.file.attribute.BasicFileAttributes;
-import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicBoolean;
 import org.apache.commons.cli.CommandLine;
 import org.apache.commons.cli.CommandLineParser;
 import org.apache.commons.cli.HelpFormatter;
@@ -46,10 +29,12 @@ import org.apache.commons.cli.Options;
 import org.apache.commons.cli.ParseException;
 import org.apache.commons.cli.PosixParser;
 import org.teavm.backend.wasm.render.WasmBinaryVersion;
+import org.teavm.tooling.ConsoleTeaVMToolLog;
 import org.teavm.tooling.TeaVMProblemRenderer;
 import org.teavm.tooling.TeaVMTargetType;
 import org.teavm.tooling.TeaVMTool;
 import org.teavm.tooling.TeaVMToolException;
+import org.teavm.tooling.util.FileSystemWatcher;
 import org.teavm.vm.TeaVMOptimizationLevel;
 import org.teavm.vm.TeaVMPhase;
 import org.teavm.vm.TeaVMProgressFeedback;
@@ -58,7 +43,7 @@ import org.teavm.vm.TeaVMProgressListener;
 public final class TeaVMRunner {
     private static Options options = new Options();
     private TeaVMTool tool = new TeaVMTool();
-    private AccumulatingTeaVMToolLog log = new AccumulatingTeaVMToolLog(new ConsoleTeaVMToolLog());
+    private AccumulatingTeaVMToolLog log = new AccumulatingTeaVMToolLog(new ConsoleTeaVMToolLog(false));
     private CommandLine commandLine;
     private long startTime;
     private long phaseStartTime;
@@ -97,12 +82,6 @@ public final class TeaVMRunner {
                 .hasArg()
                 .withArgName("number")
                 .create("O"));
-        options.addOption(OptionBuilder
-                .withArgName("separate|merge|none")
-                .hasArg()
-                .withDescription("how to attach runtime. Possible values are: separate|merge|none")
-                .withLongOpt("runtime")
-                .create("r"));
         options.addOption(OptionBuilder
                 .withDescription("Generate debug information")
                 .withLongOpt("debug")
@@ -340,30 +319,28 @@ public final class TeaVMRunner {
     }
 
     private void buildInteractive() {
-        InteractiveWatcher watcher = new InteractiveWatcher();
+        FileSystemWatcher watcher;
+        try {
+            watcher = new FileSystemWatcher(classPath);
+        } catch (IOException e) {
+            System.err.println("Error listening file system events");
+            e.printStackTrace();
+            System.exit(2);
+            return;
+        }
 
         while (true) {
-            ProgressListenerImpl progressListener = new ProgressListenerImpl();
+            ProgressListenerImpl progressListener = new ProgressListenerImpl(watcher);
-            Thread thread = null;
             try {
-                watcher.progressListener = progressListener;
-                thread = new Thread(watcher);
-                thread.start();
-                if (progressListener.cancelRequested.get()) {
-                    continue;
-                }
                 build(progressListener);
             } catch (Exception e) {
                 e.printStackTrace(System.err);
-            } finally {
-                if (!progressListener.cancelRequested.get()) {
-                    thread.interrupt();
-                }
             }
 
             try {
                 System.out.println("Waiting for changes...");
-                watcher.waitForChange();
+                watcher.waitForChange(750);
+                watcher.grabChangedFiles();
                 System.out.println();
                 System.out.println("Changes detected. Recompiling...");
             } catch (InterruptedException | IOException e) {
@@ -372,154 +349,9 @@ public final class TeaVMRunner {
         }
     }
 
-    class InteractiveWatcher implements Runnable {
-        volatile ProgressListenerImpl progressListener = new ProgressListenerImpl();
-        private WatchService watchService;
-        private Map<WatchKey, Path> keysToPath = new HashMap<>();
-        private Map<Path, WatchKey> pathsToKey = new HashMap<>();
-
-        InteractiveWatcher() {
-            try {
-                watchService = FileSystems.getDefault().newWatchService();
-                for (String entry : classPath) {
-                    Path path = Paths.get(entry);
-                    File file = path.toFile();
-                    if (file.exists()) {
-                        if (!file.isDirectory()) {
-                            registerSingle(path.getParent());
-                        } else {
-                            register(path);
-                        }
-                    }
-                }
-            } catch (IOException e) {
-                System.err.println("Error setting up file watcher");
-                e.printStackTrace(System.err);
-                System.exit(2);
-            }
-        }
-
-        private void register(Path path) throws IOException {
-            Files.walkFileTree(path, new SimpleFileVisitor<Path>() {
-                @Override
-                public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
-                        throws IOException {
-                    registerSingle(dir);
-                    return FileVisitResult.CONTINUE;
-                }
-            });
-        }
-
-        private void registerSingle(Path path) throws IOException {
-            WatchKey key = path.register(watchService, StandardWatchEventKinds.ENTRY_CREATE,
-                    StandardWatchEventKinds.ENTRY_DELETE, StandardWatchEventKinds.ENTRY_MODIFY);
-            keysToPath.put(key, path);
-            pathsToKey.put(path, key);
-        }
-
-        @Override
-        public void run() {
-            Thread thread = new Thread(() -> {
-                try {
-                    waitForChange();
-                    if (Thread.currentThread().isInterrupted()) {
-                        progressListener.cancelRequested.set(true);
-                        System.out.println("Classpath changed during compilation. Cancelling...");
-                    }
-                } catch (InterruptedException | IOException e) {
-                    // do nothing
-                }
-            });
-            thread.start();
-            if (thread.isAlive()) {
-                thread.interrupt();
-            }
-        }
-
-        void waitForChange() throws InterruptedException, IOException {
-            take();
-            while (poll(750)) {
-                // continue polling
-            }
-            while (pollNow()) {
-                // continue polling
-            }
-        }
-
-        private void take() throws InterruptedException, IOException {
-            while (true) {
-                WatchKey key = watchService.take();
-                if (key != null) {
-                    if (!filter(key).isEmpty()) {
-                        break;
-                    }
-                }
-            }
-        }
-
-        private boolean poll(int milliseconds) throws IOException, InterruptedException {
-            long end = System.currentTimeMillis() + milliseconds;
-            while (true) {
-                int timeToWait = (int) (end - System.currentTimeMillis());
-                WatchKey key = watchService.poll(timeToWait, TimeUnit.MILLISECONDS);
-                if (key == null) {
-                    return false;
-                }
-                if (!filter(key).isEmpty()) {
-                    break;
-                }
-            }
-            return true;
-        }
-
-        private boolean pollNow() throws IOException {
-            WatchKey key = watchService.poll();
-            if (key == null) {
-                return false;
-            }
-            filter(key);
-            return true;
-        }
-
-        private List<Path> filter(WatchKey key) throws IOException {
-            List<Path> result = new ArrayList<>();
-            for (WatchEvent<?> event : key.pollEvents()) {
-                Path path = filter(key, event);
-                if (path != null) {
-                    result.add(path);
-                }
-            }
-            key.reset();
-            return result;
-        }
-
-        private Path filter(WatchKey baseKey, WatchEvent<?> event) throws IOException {
-            if (!(event.context() instanceof Path)) {
-                return null;
-            }
-            Path basePath = keysToPath.get(baseKey);
-            Path path = basePath.resolve((Path) event.context());
-            WatchKey key = pathsToKey.get(path);
-
-            if (event.kind() == StandardWatchEventKinds.ENTRY_DELETE) {
-                if (key != null) {
-                    pathsToKey.remove(path);
-                    keysToPath.remove(key);
-                    key.cancel();
-                }
-            } else if (event.kind() == StandardWatchEventKinds.ENTRY_CREATE) {
-                if (Files.isDirectory(path)) {
-                    register(path);
-                }
-            }
-
-            return path;
-        }
-    }
-
     private void buildNonInteractive() {
         try {
-            build(new ProgressListenerImpl());
+            build(new ProgressListenerImpl(null));
         } catch (Exception e) {
             e.printStackTrace(System.err);
             System.exit(-2);
@@ -561,12 +393,17 @@ public final class TeaVMRunner {
 
     class ProgressListenerImpl implements TeaVMProgressListener {
         private TeaVMPhase currentPhase;
-        AtomicBoolean cancelRequested = new AtomicBoolean();
+        private FileSystemWatcher fileSystemWatcher;
+
+        ProgressListenerImpl(FileSystemWatcher fileSystemWatcher) {
+            this.fileSystemWatcher = fileSystemWatcher;
+        }
 
         @Override
         public TeaVMProgressFeedback progressReached(int progress) {
-            return cancelRequested.get() ? TeaVMProgressFeedback.CANCEL : TeaVMProgressFeedback.CONTINUE;
+            return getStatus();
         }
+
         @Override
         public TeaVMProgressFeedback phaseStarted(TeaVMPhase phase, int count) {
             log.flush();
@@ -585,16 +422,25 @@ public final class TeaVMRunner {
                     case OPTIMIZATION:
                         System.out.print("Optimizing code...");
                         break;
-                    case DECOMPILATION:
-                        System.out.print("Decompiling...");
-                        break;
                     case RENDERING:
                         System.out.print("Generating output...");
                         break;
                 }
                 currentPhase = phase;
             }
-            return cancelRequested.get() ? TeaVMProgressFeedback.CANCEL : TeaVMProgressFeedback.CONTINUE;
+            return getStatus();
+        }
+
+        private TeaVMProgressFeedback getStatus() {
+            try {
+                if (fileSystemWatcher != null && fileSystemWatcher.hasChanges()) {
+                    System.out.println("Classes changed during compilation. Canceling.");
+                    return TeaVMProgressFeedback.CANCEL;
+                }
+                return TeaVMProgressFeedback.CONTINUE;
+            } catch (IOException e) {
+                throw new RuntimeException("IO error occurred");
+            }
         }
     }
 

tools/core/src/main/java/org/teavm/tooling/ConsoleTeaVMToolLog.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2014 Alexey Andreev.
+ *  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.
@@ -13,11 +13,15 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.cli;
+package org.teavm.tooling;
 
-import org.teavm.tooling.TeaVMToolLog;
+public class ConsoleTeaVMToolLog implements TeaVMToolLog {
+    private boolean debug;
+
+    public ConsoleTeaVMToolLog(boolean debug) {
+        this.debug = debug;
+    }
 
-class ConsoleTeaVMToolLog implements TeaVMToolLog {
     @Override
     public void info(String text) {
         System.out.println("INFO: " + text);
@@ -25,8 +29,10 @@ class ConsoleTeaVMToolLog implements TeaVMToolLog {
 
     @Override
     public void debug(String text) {
+        if (debug) {
             System.out.println("DEBUG: " + text);
         }
+    }
 
     @Override
     public void warning(String text) {
@@ -46,9 +52,11 @@ class ConsoleTeaVMToolLog implements TeaVMToolLog {
 
     @Override
     public void debug(String text, Throwable e) {
+        if (debug) {
             System.out.println("DEBUG: " + text);
             e.printStackTrace(System.out);
         }
+    }
 
     @Override
     public void warning(String text, Throwable e) {

tools/core/src/main/java/org/teavm/tooling/util/FileSystemWatcher.java

@@ -0,0 +1,181 @@
+/*
+ *  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.tooling.util;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.FileSystems;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.StandardWatchEventKinds;
+import java.nio.file.WatchEvent;
+import java.nio.file.WatchKey;
+import java.nio.file.WatchService;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+public class FileSystemWatcher {
+    private WatchService watchService;
+    private Map<WatchKey, Path> keysToPath = new HashMap<>();
+    private Map<Path, WatchKey> pathsToKey = new HashMap<>();
+    private Set<File> changedFiles = new LinkedHashSet<>();
+
+    public FileSystemWatcher(String[] classPath) throws IOException {
+        watchService = FileSystems.getDefault().newWatchService();
+        for (String entry : classPath) {
+            Path path = Paths.get(entry);
+            File file = path.toFile();
+            if (file.exists()) {
+                if (!file.isDirectory()) {
+                    registerSingle(path.getParent());
+                } else {
+                    register(path);
+                }
+            }
+        }
+    }
+
+    public void dispose() throws IOException {
+        watchService.close();
+    }
+
+    private List<Path> register(Path path) throws IOException {
+        List<Path> files = new ArrayList<>();
+        Files.walkFileTree(path, new SimpleFileVisitor<Path>() {
+            @Override
+            public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {
+                registerSingle(dir);
+                files.addAll(Arrays.stream(dir.toFile().listFiles(File::isFile)).map(File::toPath)
+                        .collect(Collectors.toList()));
+                return FileVisitResult.CONTINUE;
+            }
+        });
+        return files;
+    }
+
+    private void registerSingle(Path path) throws IOException {
+        WatchKey key = path.register(watchService, StandardWatchEventKinds.ENTRY_CREATE,
+                StandardWatchEventKinds.ENTRY_DELETE, StandardWatchEventKinds.ENTRY_MODIFY);
+        keysToPath.put(key, path);
+        pathsToKey.put(path, key);
+    }
+
+    public boolean hasChanges() throws IOException {
+        return !changedFiles.isEmpty() || pollNow();
+    }
+
+    public void waitForChange(int timeout) throws InterruptedException, IOException {
+        if (!hasChanges()) {
+            take();
+        }
+        while (poll(timeout)) {
+            // continue polling
+        }
+        while (pollNow()) {
+            // continue polling
+        }
+    }
+
+    public List<File> grabChangedFiles() {
+        List<File> result = new ArrayList<>(changedFiles);
+        changedFiles.clear();
+        return result;
+    }
+
+    private void take() throws InterruptedException, IOException {
+        while (true) {
+            WatchKey key = watchService.take();
+            if (key != null && filter(key)) {
+                return;
+            }
+        }
+    }
+
+    private boolean poll(int milliseconds) throws IOException, InterruptedException {
+        long end = System.currentTimeMillis() + milliseconds;
+        while (true) {
+            int timeToWait = (int) (end - System.currentTimeMillis());
+            if (timeToWait <= 0) {
+                return false;
+            }
+            WatchKey key = watchService.poll(timeToWait, TimeUnit.MILLISECONDS);
+            if (key == null) {
+                continue;
+            }
+            if (filter(key)) {
+                return true;
+            }
+        }
+    }
+
+    private boolean pollNow() throws IOException {
+        WatchKey key = watchService.poll();
+        if (key == null) {
+            return false;
+        }
+        return filter(key);
+    }
+
+    private boolean filter(WatchKey key) throws IOException {
+        boolean hasNew = false;
+        for (WatchEvent<?> event : key.pollEvents()) {
+            List<Path> paths = filter(key, event);
+            if (!paths.isEmpty()) {
+                changedFiles.addAll(paths.stream().map(Path::toFile).collect(Collectors.toList()));
+                hasNew = true;
+            }
+        }
+        key.reset();
+        return hasNew;
+    }
+
+    private List<Path> filter(WatchKey baseKey, WatchEvent<?> event) throws IOException {
+        if (!(event.context() instanceof Path)) {
+            return Collections.emptyList();
+        }
+        Path basePath = keysToPath.get(baseKey);
+        Path path = basePath.resolve((Path) event.context());
+        WatchKey key = pathsToKey.get(path);
+
+        List<Path> result = new ArrayList<>();
+        result.add(path);
+
+        if (event.kind() == StandardWatchEventKinds.ENTRY_DELETE) {
+            if (key != null) {
+                pathsToKey.remove(path);
+                keysToPath.remove(key);
+                key.cancel();
+            }
+        } else if (event.kind() == StandardWatchEventKinds.ENTRY_CREATE) {
+            if (Files.isDirectory(path)) {
+                result.addAll(register(path));
+            }
+        }
+        return result;
+    }
+}

tools/devserver/pom.xml

@@ -0,0 +1,129 @@
+<!--
+  ~  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.
+  -->
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <parent>
+    <groupId>org.teavm</groupId>
+    <artifactId>teavm</artifactId>
+    <version>0.6.0-SNAPSHOT</version>
+    <relativePath>../..</relativePath>
+  </parent>
+  <artifactId>teavm-devserver</artifactId>
+
+  <name>TeaVM Dev Sever</name>
+  <description>TeaVM development server that builds and serves JavaScript files</description>
+
+  <dependencies>
+    <dependency>
+      <groupId>commons-io</groupId>
+      <artifactId>commons-io</artifactId>
+      <optional>true</optional>
+    </dependency>
+    <dependency>
+      <groupId>org.ow2.asm</groupId>
+      <artifactId>asm-commons</artifactId>
+      <optional>true</optional>
+    </dependency>
+    <dependency>
+      <groupId>org.ow2.asm</groupId>
+      <artifactId>asm-util</artifactId>
+      <optional>true</optional>
+    </dependency>
+    <dependency>
+      <groupId>com.carrotsearch</groupId>
+      <artifactId>hppc</artifactId>
+      <version>0.7.3</version>
+      <optional>true</optional>
+    </dependency>
+    <dependency>
+      <groupId>org.mozilla</groupId>
+      <artifactId>rhino</artifactId>
+      <optional>true</optional>
+    </dependency>
+
+    <dependency>
+      <groupId>org.teavm</groupId>
+      <artifactId>teavm-core</artifactId>
+      <version>${project.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>org.teavm</groupId>
+      <artifactId>teavm-tooling</artifactId>
+      <version>${project.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>org.teavm</groupId>
+      <artifactId>teavm-classlib</artifactId>
+      <version>${project.version}</version>
+      <scope>runtime</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.teavm</groupId>
+      <artifactId>teavm-metaprogramming-impl</artifactId>
+      <version>${project.version}</version>
+      <scope>runtime</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.teavm</groupId>
+      <artifactId>teavm-jso-impl</artifactId>
+      <version>${project.version}</version>
+      <scope>runtime</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.eclipse.jetty</groupId>
+      <artifactId>jetty-server</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>org.eclipse.jetty.websocket</groupId>
+      <artifactId>javax-websocket-server-impl</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>javax.servlet</groupId>
+      <artifactId>javax.servlet-api</artifactId>
+      <version>3.1.0</version>
+    </dependency>
+
+    <dependency>
+      <groupId>com.fasterxml.jackson.core</groupId>
+      <artifactId>jackson-databind</artifactId>
+      <optional>true</optional>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-checkstyle-plugin</artifactId>
+        <configuration>
+          <configLocation>../../checkstyle.xml</configLocation>
+          <propertyExpansion>config_loc=${basedir}/../..</propertyExpansion>
+        </configuration>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-source-plugin</artifactId>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-javadoc-plugin</artifactId>
+      </plugin>
+    </plugins>
+  </build>
+</project>

tools/devserver/src/main/java/org/teavm/devserver/CodeServlet.java

@@ -0,0 +1,566 @@
+/*
+ *  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.devserver;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.io.Reader;
+import java.io.Writer;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Supplier;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipFile;
+import java.util.zip.ZipInputStream;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import org.apache.commons.io.IOUtils;
+import org.teavm.backend.javascript.JavaScriptTarget;
+import org.teavm.cache.InMemoryMethodNodeCache;
+import org.teavm.cache.InMemoryProgramCache;
+import org.teavm.cache.MemoryCachedClassReaderSource;
+import org.teavm.debugging.information.DebugInformation;
+import org.teavm.debugging.information.DebugInformationBuilder;
+import org.teavm.dependency.FastDependencyAnalyzer;
+import org.teavm.model.ClassReader;
+import org.teavm.model.PreOptimizingClassHolderSource;
+import org.teavm.parsing.ClasspathClassHolderSource;
+import org.teavm.tooling.EmptyTeaVMToolLog;
+import org.teavm.tooling.TeaVMProblemRenderer;
+import org.teavm.tooling.TeaVMToolLog;
+import org.teavm.tooling.util.FileSystemWatcher;
+import org.teavm.vm.MemoryBuildTarget;
+import org.teavm.vm.TeaVM;
+import org.teavm.vm.TeaVMBuilder;
+import org.teavm.vm.TeaVMOptimizationLevel;
+import org.teavm.vm.TeaVMPhase;
+import org.teavm.vm.TeaVMProgressFeedback;
+import org.teavm.vm.TeaVMProgressListener;
+
+public class CodeServlet extends HttpServlet {
+    private static final Supplier<InputStream> EMPTY_CONTENT = () -> null;
+
+    private String mainClass;
+    private String[] classPath;
+    private String fileName = "classes.js";
+    private String pathToFile = "/";
+    private List<String> sourcePath = new ArrayList<>();
+    private TeaVMToolLog log = new EmptyTeaVMToolLog();
+    private boolean indicator;
+    private int port;
+
+    private Map<String, Supplier<InputStream>> sourceFileCache = new HashMap<>();
+
+    private volatile boolean stopped;
+    private FileSystemWatcher watcher;
+    private MemoryCachedClassReaderSource classSource;
+    private InMemoryProgramCache programCache;
+    private InMemoryMethodNodeCache astCache;
+    private int lastReachedClasses;
+    private boolean firstTime = true;
+
+    private final Object contentLock = new Object();
+    private final Map<String, byte[]> content = new HashMap<>();
+    private MemoryBuildTarget buildTarget = new MemoryBuildTarget();
+
+    private CodeWsEndpoint wsEndpoint;
+
+    public CodeServlet(String mainClass, String[] classPath) {
+        this.mainClass = mainClass;
+        this.classPath = classPath.clone();
+    }
+
+    public void setFileName(String fileName) {
+        this.fileName = fileName;
+    }
+
+    public void setPathToFile(String pathToFile) {
+        if (!pathToFile.endsWith("/")) {
+            pathToFile += "/";
+        }
+        if (!pathToFile.startsWith("/")) {
+            pathToFile = "/" + pathToFile;
+        }
+        this.pathToFile = pathToFile;
+    }
+
+    public List<String> getSourcePath() {
+        return sourcePath;
+    }
+
+    public void setLog(TeaVMToolLog log) {
+        this.log = log;
+    }
+
+    public void setIndicator(boolean indicator) {
+        this.indicator = indicator;
+    }
+
+    public void setPort(int port) {
+        this.port = port;
+    }
+
+    public void setWsEndpoint(CodeWsEndpoint wsEndpoint) {
+        this.wsEndpoint = wsEndpoint;
+    }
+
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
+        String path = req.getPathInfo();
+        if (path != null) {
+            log.debug("Serving " + path);
+            if (!path.startsWith("/")) {
+                path = "/" + path;
+            }
+            if (path.startsWith(pathToFile) && path.length() > pathToFile.length()) {
+                String fileName = path.substring(pathToFile.length());
+                if (fileName.startsWith("src/")) {
+                    if (serveSourceFile(fileName.substring("src/".length()), resp)) {
+                        log.debug("File " + path + " served as source file");
+                        return;
+                    }
+                } else {
+                    byte[] fileContent;
+                    boolean firstTime;
+                    synchronized (contentLock) {
+                        fileContent = content.get(fileName);
+                        firstTime = this.firstTime;
+                    }
+                    if (fileContent != null) {
+                        resp.setStatus(HttpServletResponse.SC_OK);
+                        resp.setCharacterEncoding("UTF-8");
+                        resp.setContentType("text/plain");
+                        resp.getOutputStream().write(fileContent);
+                        resp.getOutputStream().flush();
+                        log.debug("File " + path + " served as generated file");
+                        return;
+                    } else if (fileName.equals(this.fileName) && indicator && firstTime) {
+                        serveBootFile(resp);
+                        return;
+                    }
+                }
+            }
+        }
+
+        log.debug("File " + path + " not found");
+        resp.setStatus(HttpServletResponse.SC_NOT_FOUND);
+    }
+
+    @Override
+    public void destroy() {
+        super.destroy();
+        stopped = true;
+    }
+
+    @Override
+    public void init() throws ServletException {
+        super.init();
+        Thread thread = new Thread(this::runTeaVM);
+        thread.setDaemon(true);
+        thread.setName("TeaVM compiler");
+        thread.start();
+    }
+
+    private boolean serveSourceFile(String fileName, HttpServletResponse resp) throws IOException {
+        try (InputStream stream = sourceFileCache.computeIfAbsent(fileName, this::findSourceFile).get()) {
+            if (stream == null) {
+                return false;
+            }
+
+            resp.setStatus(HttpServletResponse.SC_OK);
+            resp.setCharacterEncoding("UTF-8");
+            resp.setContentType("text/plain");
+            IOUtils.copy(stream, resp.getOutputStream());
+            resp.getOutputStream().flush();
+            return true;
+        }
+    }
+
+    private Supplier<InputStream> findSourceFile(String fileName) {
+        for (String element : sourcePath) {
+            File sourceFile = new File(element);
+            if (sourceFile.isFile()) {
+                Supplier<InputStream> result = findSourceFileInZip(sourceFile, fileName);
+                if (result != null) {
+                    return result;
+                }
+            } else if (sourceFile.isDirectory()) {
+                File result = new File(sourceFile, fileName);
+                if (result.exists()) {
+                    return () -> {
+                        try {
+                            return new FileInputStream(result);
+                        } catch (FileNotFoundException e) {
+                            return null;
+                        }
+                    };
+                }
+            }
+        }
+
+        return EMPTY_CONTENT;
+    }
+
+    private Supplier<InputStream> findSourceFileInZip(File zipFile, String fileName) {
+        try (ZipFile zip = new ZipFile(zipFile)) {
+            ZipEntry entry = zip.getEntry(fileName);
+            if (entry == null) {
+                return null;
+            }
+            return () -> {
+                try {
+                    ZipInputStream input = new ZipInputStream(new FileInputStream(zipFile));
+                    while (true) {
+                        ZipEntry e = input.getNextEntry();
+                        if (e == null) {
+                            return null;
+                        }
+                        if (e.getName().equals(fileName)) {
+                            return input;
+                        }
+                    }
+                } catch (IOException e) {
+                    return null;
+                }
+            };
+        } catch (IOException e) {
+            return null;
+        }
+    }
+
+    private void serveBootFile(HttpServletResponse resp) throws IOException {
+        resp.setStatus(HttpServletResponse.SC_OK);
+        resp.setCharacterEncoding("UTF-8");
+        resp.setContentType("text/plain");
+        resp.getWriter().write("function main() { }\n");
+        resp.getWriter().write(getIndicatorScript(true));
+        resp.getWriter().flush();
+        log.debug("Served boot file");
+    }
+
+    private void runTeaVM() {
+        try {
+            initBuilder();
+
+            while (!stopped) {
+                buildOnce();
+
+                if (stopped) {
+                    break;
+                }
+
+                try {
+                    watcher.waitForChange(750);
+                } catch (InterruptedException e) {
+                    log.info("Build thread interrupted");
+                    break;
+                }
+                log.info("Changes detected. Recompiling.");
+                List<String> staleClasses = getChangedClasses(watcher.grabChangedFiles());
+                log.debug("Following classes changed: " + staleClasses);
+                classSource.evict(staleClasses);
+            }
+        } catch (Throwable e) {
+            log.error("Compile server crashed", e);
+        } finally {
+            shutdownBuilder();
+        }
+    }
+
+    private void initBuilder() throws IOException {
+        watcher = new FileSystemWatcher(classPath);
+
+        classSource = new MemoryCachedClassReaderSource();
+        astCache = new InMemoryMethodNodeCache();
+        programCache = new InMemoryProgramCache();
+    }
+
+    private void shutdownBuilder() {
+        try {
+            watcher.dispose();
+        } catch (IOException e) {
+            log.debug("Exception caught", e);
+        }
+        classSource = null;
+        watcher = null;
+        astCache = null;
+        programCache = null;
+        synchronized (content) {
+            content.clear();
+        }
+        buildTarget.clear();
+
+        log.info("Build thread complete");
+    }
+
+    private void buildOnce() {
+        DebugInformationBuilder debugInformationBuilder = new DebugInformationBuilder();
+        ClassLoader classLoader = initClassLoader();
+        classSource.setUnderlyingSource(new PreOptimizingClassHolderSource(
+                new ClasspathClassHolderSource(classLoader)));
+
+        long startTime = System.currentTimeMillis();
+        JavaScriptTarget jsTarget = new JavaScriptTarget();
+
+        TeaVM vm = new TeaVMBuilder(jsTarget)
+                .setClassLoader(classLoader)
+                .setClassSource(classSource)
+                .setDependencyAnalyzerFactory(FastDependencyAnalyzer::new)
+                .build();
+
+        jsTarget.setStackTraceIncluded(true);
+        jsTarget.setMinifying(false);
+        jsTarget.setAstCache(astCache);
+        jsTarget.setDebugEmitter(debugInformationBuilder);
+        vm.setOptimizationLevel(TeaVMOptimizationLevel.SIMPLE);
+        vm.setCacheStatus(classSource);
+        vm.addVirtualMethods(m -> true);
+        vm.setProgressListener(progressListener);
+        vm.setProgramCache(programCache);
+        vm.installPlugins();
+
+        vm.setLastKnownClasses(lastReachedClasses);
+        vm.entryPoint(mainClass);
+
+        log.info("Starting build");
+        progressListener.last = 0;
+        progressListener.lastTime = System.currentTimeMillis();
+        vm.build(buildTarget, fileName);
+        addIndicator();
+        generateDebug(debugInformationBuilder);
+
+        postBuild(vm, startTime);
+    }
+
+    private void addIndicator() {
+        if (!indicator) {
+            return;
+        }
+
+        String script = getIndicatorScript(false);
+        try (Writer writer = new OutputStreamWriter(buildTarget.appendToResource(fileName), StandardCharsets.UTF_8)) {
+            writer.append("\n");
+            writer.append(script);
+        } catch (IOException e) {
+            throw new RuntimeException("IO error occurred writing debug information", e);
+        }
+    }
+
+    private String getIndicatorScript(boolean boot) {
+        try (Reader reader = new InputStreamReader(CodeServlet.class.getResourceAsStream("indicator.js"),
+                StandardCharsets.UTF_8)) {
+            String script = IOUtils.toString(reader);
+            script = script.substring(script.indexOf("*/") + 2);
+            script = script.replace("WS_PATH", "localhost:" + port + pathToFile + fileName + ".ws");
+            script = script.replace("BOOT_FLAG", Boolean.toString(boot));
+            script = script.replace("FILE_NAME", "http://localhost:" + port + pathToFile + fileName);
+            return script;
+        } catch (IOException e) {
+            throw new RuntimeException("IO error occurred writing debug information", e);
+        }
+    }
+
+    private void generateDebug(DebugInformationBuilder debugInformationBuilder) {
+        try {
+            DebugInformation debugInformation = debugInformationBuilder.getDebugInformation();
+            String sourceMapName = fileName + ".map";
+
+            try (Writer writer = new OutputStreamWriter(buildTarget.appendToResource(fileName),
+                    StandardCharsets.UTF_8)) {
+                writer.append("\n//# sourceMappingURL=" + sourceMapName);
+            }
+
+            try (Writer writer = new OutputStreamWriter(buildTarget.createResource(sourceMapName),
+                    StandardCharsets.UTF_8)) {
+                debugInformation.writeAsSourceMaps(writer, "src", fileName);
+            }
+            debugInformation.write(buildTarget.createResource(fileName + ".teavmdbg"));
+        } catch (IOException e) {
+            throw new RuntimeException("IO error occurred writing debug information", e);
+        }
+    }
+
+    private void postBuild(TeaVM vm, long startTime) {
+        if (!vm.wasCancelled()) {
+            if (vm.getProblemProvider().getSevereProblems().isEmpty()) {
+                log.info("Build complete successfully");
+                saveNewResult();
+                lastReachedClasses = vm.getDependencyInfo().getReachableClasses().size();
+                classSource.commit();
+                if (wsEndpoint != null) {
+                    wsEndpoint.complete(true);
+                }
+            } else {
+                log.info("Build complete with errors");
+                if (wsEndpoint != null) {
+                    wsEndpoint.complete(false);
+                }
+            }
+            printStats(vm, startTime);
+            TeaVMProblemRenderer.describeProblems(vm, log);
+        } else {
+            log.info("Build cancelled");
+        }
+
+        buildTarget.clear();
+    }
+
+    private void printStats(TeaVM vm, long startTime) {
+        if (vm.getWrittenClasses() != null) {
+            int classCount = vm.getWrittenClasses().getClassNames().size();
+            int methodCount = 0;
+            for (String className : vm.getWrittenClasses().getClassNames()) {
+                ClassReader cls = vm.getWrittenClasses().get(className);
+                methodCount += cls.getMethods().size();
+            }
+
+            log.info("Classes compiled: " + classCount);
+            log.info("Methods compiled: " + methodCount);
+        }
+
+        log.info("Compilation took " + (System.currentTimeMillis() - startTime) + " ms");
+    }
+
+    private void saveNewResult() {
+        synchronized (contentLock) {
+            firstTime = false;
+            content.clear();
+            for (String name : buildTarget.getNames()) {
+                content.put(name, buildTarget.getContent(name));
+            }
+        }
+    }
+
+    private List<String> getChangedClasses(Collection<File> changedFiles) {
+        List<String> result = new ArrayList<>();
+
+        for (File file : changedFiles) {
+            String path = file.getPath();
+            if (!path.endsWith(".class")) {
+                continue;
+            }
+
+            String prefix = Arrays.stream(classPath)
+                    .filter(path::startsWith)
+                    .findFirst()
+                    .orElse("");
+            int start = prefix.length();
+            if (start < path.length() && path.charAt(start) == '/') {
+                ++start;
+            }
+
+            path = path.substring(start, path.length() - ".class".length()).replace('/', '.');
+            result.add(path);
+        }
+
+        return result;
+    }
+
+    private ClassLoader initClassLoader() {
+        URL[] urls = new URL[classPath.length];
+        try {
+            for (int i = 0; i < classPath.length; i++) {
+                urls[i] = new File(classPath[i]).toURI().toURL();
+            }
+        } catch (MalformedURLException e) {
+            throw new RuntimeException(e);
+        }
+        return new URLClassLoader(urls, CodeServlet.class.getClassLoader());
+    }
+
+    private final ProgressListenerImpl progressListener = new ProgressListenerImpl();
+
+    class ProgressListenerImpl implements TeaVMProgressListener {
+        private int start;
+        private int end;
+        private int phaseLimit;
+        private int last;
+        private long lastTime;
+
+        @Override
+        public TeaVMProgressFeedback phaseStarted(TeaVMPhase phase, int count) {
+            switch (phase) {
+                case DEPENDENCY_ANALYSIS:
+                    start = 0;
+                    end = 500;
+                    break;
+                case LINKING:
+                    start = 400;
+                    end = 500;
+                    break;
+                case OPTIMIZATION:
+                    start = 500;
+                    end = 750;
+                    break;
+                case RENDERING:
+                    start = 750;
+                    end = 1000;
+                    break;
+            }
+            phaseLimit = count;
+            return progressReached(0);
+        }
+
+        @Override
+        public TeaVMProgressFeedback progressReached(int progress) {
+            if (wsEndpoint != null && indicator) {
+                int current = start + Math.min(progress, phaseLimit) * (end - start) / phaseLimit;
+                if (current != last) {
+                    if (current - last > 10 || System.currentTimeMillis() - lastTime > 100) {
+                        lastTime = System.currentTimeMillis();
+                        last = current;
+                        wsEndpoint.progress(current / 10.0);
+                    }
+                }
+            }
+            return getResult();
+        }
+
+        private TeaVMProgressFeedback getResult() {
+            if (stopped) {
+                log.info("Trying to cancel compilation due to server stopping");
+                return TeaVMProgressFeedback.CANCEL;
+            }
+
+            try {
+                if (watcher.hasChanges()) {
+                    log.info("Changes detected, cancelling build");
+                    return TeaVMProgressFeedback.CANCEL;
+                }
+            } catch (IOException e) {
+                log.info("IO error occurred", e);
+                return TeaVMProgressFeedback.CANCEL;
+            }
+
+            return TeaVMProgressFeedback.CONTINUE;
+        }
+    }
+}

tools/devserver/src/main/java/org/teavm/devserver/CodeWsEndpoint.java

@@ -0,0 +1,44 @@
+/*
+ *  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.devserver;
+
+import java.util.function.Consumer;
+import javax.websocket.OnOpen;
+import javax.websocket.Session;
+import javax.websocket.server.ServerEndpoint;
+
+@ServerEndpoint("/")
+public class CodeWsEndpoint {
+    private Session session;
+
+    @OnOpen
+    public void open(Session session) {
+        this.session = session;
+        @SuppressWarnings("unchecked")
+        Consumer<CodeWsEndpoint> consumer = (Consumer<CodeWsEndpoint>) session.getUserProperties().get("ws.consumer");
+        if (consumer != null) {
+            consumer.accept(this);
+        }
+    }
+
+    public void progress(double value) {
+        session.getAsyncRemote().sendText("{ \"command\": \"compiling\", \"progress\": " + value + " }");
+    }
+
+    public void complete(boolean success) {
+        session.getAsyncRemote().sendText("{ \"command\": \"complete\", \"success\": " + success + " }");
+    }
+}

tools/devserver/src/main/java/org/teavm/devserver/DevServer.java

@@ -0,0 +1,170 @@
+/*
+ *  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.devserver;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Consumer;
+import javax.websocket.Decoder;
+import javax.websocket.Encoder;
+import javax.websocket.Extension;
+import javax.websocket.server.ServerContainer;
+import javax.websocket.server.ServerEndpointConfig;
+import org.eclipse.jetty.server.Server;
+import org.eclipse.jetty.server.ServerConnector;
+import org.eclipse.jetty.servlet.ServletContextHandler;
+import org.eclipse.jetty.servlet.ServletHolder;
+import org.eclipse.jetty.websocket.jsr356.server.deploy.WebSocketServerContainerInitializer;
+import org.teavm.tooling.ConsoleTeaVMToolLog;
+import org.teavm.tooling.TeaVMToolLog;
+
+public class DevServer {
+    private String mainClass;
+    private String[] classPath;
+    private String pathToFile = "";
+    private String fileName = "classes.js";
+    private List<String> sourcePath = new ArrayList<>();
+    private boolean indicator;
+    private TeaVMToolLog log = new ConsoleTeaVMToolLog(false);
+
+    private Server server;
+    private int port = 9090;
+
+    public void setMainClass(String mainClass) {
+        this.mainClass = mainClass;
+    }
+
+    public void setClassPath(String[] classPath) {
+        this.classPath = classPath;
+    }
+
+    public void setPort(int port) {
+        this.port = port;
+    }
+
+    public void setPathToFile(String pathToFile) {
+        if (!pathToFile.startsWith("/")) {
+            pathToFile = "/" + pathToFile;
+        }
+        if (!pathToFile.endsWith("/")) {
+            pathToFile += "/";
+        }
+        this.pathToFile = pathToFile;
+    }
+
+    public void setLog(TeaVMToolLog log) {
+        this.log = log;
+    }
+
+    public void setFileName(String fileName) {
+        this.fileName = fileName;
+    }
+
+    public void setIndicator(boolean indicator) {
+        this.indicator = indicator;
+    }
+
+    public List<String> getSourcePath() {
+        return sourcePath;
+    }
+
+    public void start() {
+        server = new Server();
+        ServerConnector connector = new ServerConnector(server);
+        connector.setPort(port);
+        server.addConnector(connector);
+
+        ServletContextHandler context = new ServletContextHandler(ServletContextHandler.SESSIONS);
+        context.setContextPath("/");
+        server.setHandler(context);
+        CodeServlet servlet = new CodeServlet(mainClass, classPath);
+        servlet.setFileName(fileName);
+        servlet.setPathToFile(pathToFile);
+        servlet.setLog(log);
+        servlet.getSourcePath().addAll(sourcePath);
+        servlet.setIndicator(indicator);
+        servlet.setPort(port);
+        context.addServlet(new ServletHolder(servlet), "/*");
+
+        try {
+            ServerContainer wscontainer = WebSocketServerContainerInitializer.configureContext(context);
+            wscontainer.addEndpoint(new DevServerEndpointConfig(servlet::setWsEndpoint));
+            server.start();
+            server.join();
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public void stop() {
+        try {
+            server.stop();
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private class DevServerEndpointConfig implements ServerEndpointConfig {
+        private Map<String, Object> userProperties = new HashMap<>();
+
+        public DevServerEndpointConfig(Consumer<CodeWsEndpoint> consumer) {
+            userProperties.put("ws.consumer", consumer);
+        }
+
+        @Override
+        public List<Class<? extends Decoder>> getDecoders() {
+            return Collections.emptyList();
+        }
+
+        @Override
+        public List<Class<? extends Encoder>> getEncoders() {
+            return Collections.emptyList();
+        }
+
+        @Override
+        public Map<String, Object> getUserProperties() {
+            return userProperties;
+        }
+
+        @Override
+        public Configurator getConfigurator() {
+            return null;
+        }
+
+        @Override
+        public Class<?> getEndpointClass() {
+            return CodeWsEndpoint.class;
+        }
+
+        @Override
+        public List<Extension> getExtensions() {
+            return Collections.emptyList();
+        }
+
+        @Override
+        public String getPath() {
+            return pathToFile + fileName + ".ws";
+        }
+
+        @Override
+        public List<String> getSubprotocols() {
+            return Collections.emptyList();
+        }
+    }
+}

tools/devserver/src/main/resources/org/teavm/devserver/indicator.js

@@ -0,0 +1,153 @@
+/*
+ *  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.
+ */
+(function () {
+    var boot = BOOT_FLAG;
+
+    function createWebSocket() {
+        var loc = window.location;
+        var newUri = loc.protocol === "https:" ? "wss:" : "ws:";
+        newUri += "//WS_PATH";
+        return new WebSocket(newUri);
+    }
+
+    function createIndicator() {
+        function createMainElement() {
+            var element = document.createElement("div");
+            element.style.position = "fixed";
+            element.style.left = "0";
+            element.style.bottom = "0";
+            element.style.backgroundColor = "black";
+            element.style.color = "white";
+            element.style.opacity = 0.4;
+            element.style.padding = "5px";
+            element.style.fontSize = "18px";
+            element.style.fontWeight = "bold";
+            element.style.pointerEvents = "none";
+            element.style.zIndex = 1000;
+            element.style.display = "none";
+            return element;
+        }
+
+        function createLabelElement() {
+            return document.createElement("span");
+        }
+
+        function createProgressElements() {
+            var element = document.createElement("span");
+            element.style.display = "none";
+            element.style.marginLeft = "10px";
+            element.style.width = "150px";
+            element.style.height = "15px";
+            element.style.borderWidth = "1px";
+            element.style.borderColor = "rgb(170,170,170)";
+            element.style.borderStyle = "solid";
+            element.style.borderRadius = "2px";
+            element.style.backgroundColor = "white";
+            element.style.position = "relative";
+
+            var progress = document.createElement("span");
+            progress.style.display = "block";
+            progress.style.position = "absolute";
+            progress.style.left = "0";
+            progress.style.top = "0";
+            progress.style.bottom = "0";
+            progress.style.backgroundColor = "rgb(210,210,210)";
+            progress.style.borderWidth = "1px";
+            progress.style.borderColor = "rgb(170,170,170)";
+            progress.style.borderRightStyle = "solid";
+
+            element.appendChild(progress);
+
+            return {
+                container: element,
+                indicator: progress
+            };
+        }
+
+        var container = createMainElement();
+        var label = createLabelElement();
+        var progress = createProgressElements();
+        container.appendChild(label);
+        container.appendChild(progress.container);
+
+        return {
+            container: container,
+            label: label,
+            progress: progress,
+            timer: void 0,
+
+            show: function(text, timeout) {
+                this.container.style.display = "";
+                this.label.innerText = text;
+                if (this.timer) {
+                    clearTimeout(this.timer);
+                    this.timer = void 0;
+                }
+                if (timeout) {
+                    setTimeout(function() {
+                        this.timer = void 0;
+                        this.container.style.display = "none";
+                    }.bind(this), timeout * 1000);
+                }
+            },
+
+            showProgress(value) {
+                this.progress.container.style.display = "inline-block";
+                this.progress.indicator.style.width = value.toFixed(2) + "%";
+            },
+
+            hideProgress() {
+                this.progress.container.style.display = "none";
+            }
+        };
+    }
+
+    var indicator = createIndicator();
+    window.addEventListener("load", function() {
+        document.body.appendChild(indicator.container);
+    });
+
+    var ws = createWebSocket();
+    ws.onmessage = function(event) {
+        var message = JSON.parse(event.data);
+        switch (message.command) {
+            case "compiling":
+                indicator.show("Compiling...");
+                indicator.showProgress(message.progress || 0);
+                break;
+            case "complete":
+                if (message.success) {
+                    indicator.show("Compilation complete", 10);
+                    if (boot) {
+                        var scriptElem = document.createElement("script");
+                        scriptElem.src = "FILE_NAME";
+                        scriptElem.onload = function() {
+                            main();
+                        };
+                        document.head.appendChild(scriptElem);
+                    }
+                } else {
+                    indicator.show("Compilation errors occurred")
+                }
+                indicator.hideProgress();
+                break;
+        }
+    };
+
+    if (boot) {
+        indicator.show("File is not ready, about to compile");
+    }
+})();

tools/idea/jps-plugin/src/main/java/org/teavm/idea/jps/TeaVMBuild.java

@@ -182,8 +182,6 @@ class TeaVMBuild {
                 return "Discovering classes to compile";
             case LINKING:
                 return "Resolving method invocations";
-            case DECOMPILATION:
-                return "Compiling classes";
             case OPTIMIZATION:
                 return "Optimizing code";
             case RENDERING: