Java Code Examples for org.objectweb.asm.ClassWriter#visitEnd()

public Class<?> translate(Plugin plugin) throws IOException {
    // 防止出现 Class not found 的奇葩问题，使用缓存（目的是兼容热重载）
    InputStream inputStream = useCache ? new ByteArrayInputStream(cacheClasses.computeIfAbsent(target, n -> {
        try {
            return IO.readFully(Files.getResource(plugin, target.replace(".", "/") + ".class"));
        } catch (IOException e) {
            e.printStackTrace();
        }
        return new byte[0];
    })) : Files.getResource(plugin, target.replace(".", "/") + ".class");
    // 读取
    ClassReader classReader = new ClassReader(inputStream);
    ClassWriter classWriter = new ClassWriter(0);
    ClassVisitor classVisitor = new SimpleClassVisitor(this, classWriter);
    classReader.accept(classVisitor, ClassReader.EXPAND_FRAMES);
    classWriter.visitEnd();
    classVisitor.visitEnd();
    // 打印
    if (mapping || plugin instanceof InternalPlugin) {
        executorService.submit(this::printMapping);
    }
    // 因第三方插件调用该方法时会出现找不到类，所以第三方插件使用 BridgeLoader 加载类
    return plugin instanceof InternalPlugin ? AsmClassLoader.createNewClass(target, classWriter.toByteArray()) : BridgeLoader.createNewClass(target, classWriter.toByteArray());
}
 

static byte[] create() throws IOException {
    ClassReader reader = new ClassReader(FaviconExceptionMapper.class.getClassLoader().getResourceAsStream(FaviconExceptionMapper.class.getName().replace('.', '/') + ".class"));

    ClassWriter writer = new ClassWriter(0);
    Remapper remapper = new Remapper() {
        @Override
        public String map(String typeName) {
            if (typeName.equals("org/wildfly/swarm/jaxrs/internal/FaviconExceptionMapper")) {
                return "org/wildfly/swarm/generated/FaviconExceptionMapper";
            }
            return super.map(typeName);
        }
    };

    RemappingClassAdapter adapter = new RemappingClassAdapter(writer, remapper);
    reader.accept(adapter, 0);

    writer.visitAnnotation("Ljavax/ws/rs/ext/Provider;", true).visitEnd();
    writer.visitEnd();

    return writer.toByteArray();
}
 

/**
 * Generates and returns the bytecode for an exception class.
 * 
 * @param name The name of the class to generate.
 * @param superName The name of the superclass.
 * @return The bytecode for the new class.
 */
public static byte[] generateExceptionClass(String name, String superName) {
    ClassWriter out = new ClassWriter(ClassWriter.COMPUTE_FRAMES | ClassWriter.COMPUTE_MAXS);
    
    // This class only exists to be a type - the superclasses always do everything.
    // (common access for all classes we generate - public and "super", meaning post-1.1 invokestatic).
    int access = Opcodes.ACC_PUBLIC | Opcodes.ACC_SUPER;
    // We ignore generics, so null signature.
    String signature = null;
    // We implement no interfaces.
    String[] interfaces = new String[0];
    out.visit(CLASS_VERSION, access, name, signature, superName, interfaces);
    
    // Generate the constructors.
    populateExceptionConstructors(out, superName);
    
    // Finish this and dump the bytes.
    out.visitEnd();
    return out.toByteArray();
}
 

/**
 * Creates a new class prepared to be loaded into the {@link ClassLoader}.
 *
 * @param type The type of class to implement
 * @param name The name of the class
 * @param exceptionType The exception type to throw for all methods
 * @return The generated class
 */
public byte[] createClass(final Class<?> type, final String name, final Class<?> exceptionType) {

    checkNotNull(type, "type");
    checkNotNull(name, "name");
    checkNotNull(exceptionType, "exception");

    checkState(type.isInterface(), String.format("Class %s is not an interface!", type));
    checkState(Throwable.class.isAssignableFrom(exceptionType), String.format("Class %s does not extend Throwable!", exceptionType));

    String internalName = name.replace('.', '/');
    List<Method> methods = this.getInterfaceMethods(type);

    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
    cw.visit(V1_8, ACC_PUBLIC + ACC_SUPER, internalName, null, Type.getInternalName(Object.class), new String[] {Type.getInternalName(type)});

    this.generateConstructor(cw, internalName);
    this.generateMethods(cw, internalName, methods, exceptionType);

    cw.visitEnd();

    return cw.toByteArray();
}
 

private void loadMagic() {
    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
    cw.visit(Opcodes.V1_4, Opcodes.ACC_PUBLIC, "sun/reflect/GroovyMagic", null, "sun/reflect/MagicAccessorImpl", null);
    MethodVisitor mv = cw.visitMethod(Opcodes.ACC_PUBLIC, "<init>", "()V", null, null);
    mv.visitCode();
    mv.visitVarInsn(ALOAD, 0);
    mv.visitMethodInsn(INVOKESPECIAL, "sun/reflect/MagicAccessorImpl", "<init>", "()V", false);
    mv.visitInsn(RETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();
    cw.visitEnd();

    define(cw.toByteArray(), "sun.reflect.GroovyMagic");
}
 

/**
 * Creates AppPerformanceConfig.class file with a static boolean field AppPerformanceConfig#enabled in it.
 *
 * @param value Initializes the AppPerformanceConfig#enabled with value.
 * @return byte array of the class.
 */
public static byte[] generateConfigClass(boolean value) {

  ClassWriter cw = new ClassWriter(0);
  cw.visit(V1_6, ACC_FINAL + ACC_SUPER,
      "com/rakuten/tech/mobile/perf/runtime/internal/AppPerformanceConfig", null,
      "java/lang/Object", null);
  cw.visitField(ACC_PUBLIC + ACC_STATIC, "enabled", "Z", null, value);
  cw.visitEnd();
  return cw.toByteArray();
}
 

@Test
public void testExhaustion() {
  // 2^16 is a lot of classes.  This should exhaust the metaspace
  // (set on the command line to 32MB, if there is a class leak.
  final int classCount = 65536;

  ClassWriter cw = new ClassWriter(0);
  cw.visit(
      Opcodes.V1_6,
      Opcodes.ACC_PUBLIC,
      "com/google/monitoring/runtime/agentdetection/AgentPresent",
      null,
      "java/lang/Object",
      null);
  cw.visitEnd();
  byte[] classBytes = cw.toByteArray();

  // Uncommenting the lines related to the Class<?> array will cause
  // metaspace exhaustion.  This can be used for testing.
  // Class<?>[] cs = new Class<?>[classCount];
  for (int i = 0; i < classCount; i++) {
    // Load the perfectly legitimate class in its own class loader
    // (so as to prevent the class loader from complaining about
    // name clashes).
    LocalLoader l = new LocalLoader();
    // cs[i] =
    l.findClass("com.google.monitoring.runtime.agentdetection.AgentPresent", classBytes);
  }
}
 

public static byte[] dump(String name) {
  ClassWriter cw = new ClassWriter(0);
  cw.visit(52, Opcodes.ACC_PUBLIC + Opcodes.ACC_SUPER, name, null, "java/lang/Object", null);
  {
    MethodVisitor mv = cw.visitMethod(Opcodes.ACC_PUBLIC, "<init>", "()V", null, null);
    mv.visitCode();
    mv.visitVarInsn(Opcodes.ALOAD, 0);
    mv.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);
    mv.visitInsn(Opcodes.RETURN);
    mv.visitMaxs(1, 1);
    mv.visitEnd();
  }
  cw.visitEnd();
  return cw.toByteArray();
}
 

@Test
public void genClass()
{
    ClassWriter classWriter = new ClassWriter(0);
    classWriter.visit(V1_6, ACC_PUBLIC + ACC_ABSTRACT + ACC_INTERFACE,
            "cn/edu/ruc/iir/paraflow/loader/consumer/utils/Comparable",
            null,
            "java/lang/Object",
            null);
    classWriter.visitField(ACC_PUBLIC + ACC_FINAL + ACC_STATIC,
            "LESS", "I", null, -1)
            .visitEnd();
    classWriter.visitField(ACC_PUBLIC + ACC_FINAL + ACC_STATIC,
            "EQUAL", "I", null, 0)
            .visitEnd();
    classWriter.visitField(ACC_PUBLIC + ACC_FINAL + ACC_STATIC,
            "GREATER", "I", null, 1)
            .visitEnd();
    classWriter.visitMethod(ACC_PUBLIC + ACC_ABSTRACT,
            "compareTo", "(Ljava/lang/Object;)I", null, null)
            .visitEnd();
    classWriter.visitEnd();
    byte[] bytes = classWriter.toByteArray();

    MyClassLoader myClassLoader = new MyClassLoader();
    Class clazz = myClassLoader.defineClass("cn.edu.ruc.iir.paraflow.loader.consumer.utils.Comparable", bytes);
    try {
        System.out.println(clazz.getField("LESS").getName());
    }
    catch (NoSuchFieldException e) {
        e.printStackTrace();
    }
}
 

private LazyDefinedClass generate() {
    LazyDefinedClass methodMetaClass = null;
    if (methodMetaInternalName != null) {
        methodMetaClass = generateMethodMetaClass(config);
    }
    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
    String[] interfaces = null;
    if (!config.enabledProperty().isEmpty() || !config.traceEntryEnabledProperty().isEmpty()) {
        interfaces = new String[] {"org/glowroot/agent/plugin/api/config/ConfigListener"};
    }
    cw.visit(V1_5, ACC_PUBLIC + ACC_SUPER, adviceInternalName, null, "java/lang/Object",
            interfaces);
    addClassAnnotation(cw);
    addStaticFields(cw);
    addStaticInitializer(cw);
    boolean checkNotInTransaction = config.isTransaction()
            && config.alreadyInTransactionBehavior() == AlreadyInTransactionBehavior.DO_NOTHING;
    boolean checkPropertyNotEnabled = pluginId != null && !config.enabledProperty().isEmpty();
    addIsEnabledMethodIfNeeded(cw, checkNotInTransaction, checkPropertyNotEnabled);
    if (config.isTraceEntryOrGreater()) {
        // methodMetaInternalName is non-null when entry or greater
        checkNotNull(methodMetaInternalName);
        addOnBeforeMethod(cw);
        addOnThrowMethod(cw);
        addOnReturnMethod(cw);
    } else if (config.captureKind() == CaptureKind.TIMER) {
        addOnBeforeMethodTimerOnly(cw);
        addOnAfterMethodTimerOnly(cw);
    } else {
        addOnBeforeMethodOther(cw);
    }
    cw.visitEnd();
    ImmutableLazyDefinedClass.Builder builder = ImmutableLazyDefinedClass.builder()
            .type(Type.getObjectType(adviceInternalName))
            .bytes(cw.toByteArray());
    if (methodMetaClass != null) {
        builder.addDependencies(methodMetaClass);
    }
    return builder.build();
}
 

private Class<?> createClass(ClassPair classPair) {
  String className = generateClassName(classPair);
  String classStr = className.replaceAll("\\.", "/");

  String keyClassType = Type.getDescriptor(classPair.keyClass);
  String valueClassType = Type.getDescriptor(classPair.valueClass);

  ClassWriter cw = new ClassWriter(0);
  cw.visit(V1_7, ACC_PUBLIC + ACC_SUPER, className, null, "java/lang/Object", new String[]{interfaceName});

  AnnotationVisitor anno = cw.visitAnnotation(Type.getDescriptor(JsonPropertyOrder.class), true);
  AnnotationVisitor aa = anno.visitArray("value");
  aa.visit("", "key");
  aa.visit("", "value");
  aa.visitEnd();
  anno.visitEnd();

  FieldVisitor keyField = cw.visitField(ACC_PRIVATE, "key", keyClassType, null, null);
  keyField.visitEnd();

  FieldVisitor valueField = cw.visitField(ACC_PRIVATE, "value", valueClassType, null, null);
  valueField.visitEnd();

  MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
  mv.visitMaxs(2, 1);
  mv.visitVarInsn(ALOAD, 0);
  mv.visitMethodInsn(INVOKESPECIAL, Type.getInternalName(Object.class), "<init>", "()V", false); // call the constructor of super class
  mv.visitInsn(RETURN);
  mv.visitEnd();

  addGetterSetter(classPair, className, classStr, keyClassType, valueClassType, cw);
  addKVPairMethods(classPair, className, classStr, keyClassType, valueClassType, cw);

  cw.visitEnd();

  return defineClass(className, cw.toByteArray());
}
 

static byte[] dump() {

    ClassWriter cw = new ClassWriter(0);
    FieldVisitor fv;
    MethodVisitor mv;
    AnnotationVisitor av0;

    cw.visit(52, ACC_FINAL + ACC_SUPER, CLASS_PACKAGE, null, "java/lang/Object", null);

    {
      fv = cw.visitField(ACC_PRIVATE, "credentials", "L" + SUN_SECURITY_KRB_5_CREDENTIALS + ";", null, null);
      fv.visitEnd();
    }
    {
      mv = cw.visitMethod(0, "<init>", "()V", null, null);
      mv.visitCode();
      mv.visitVarInsn(ALOAD, 0);
      mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);
      mv.visitInsn(RETURN);
      mv.visitMaxs(1, 1);
      mv.visitEnd();
    }
    {
      mv = cw.visitMethod(ACC_PUBLIC, "getCredentials", "()L" + SUN_SECURITY_KRB_5_CREDENTIALS + ";", null, null);
      mv.visitCode();
      mv.visitVarInsn(ALOAD, 0);
      mv.visitFieldInsn(GETFIELD, CLASS_PACKAGE, "credentials", "L" + SUN_SECURITY_KRB_5_CREDENTIALS + ";");
      mv.visitInsn(ARETURN);
      mv.visitMaxs(1, 1);
      mv.visitEnd();
    }
    {
      mv = cw.visitMethod(ACC_PUBLIC, "setCredentials", "(L" + SUN_SECURITY_KRB_5_CREDENTIALS + ";)V", null, null);
      mv.visitCode();
      mv.visitVarInsn(ALOAD, 0);
      mv.visitVarInsn(ALOAD, 1);
      mv.visitFieldInsn(PUTFIELD, CLASS_PACKAGE, "credentials", "L" + SUN_SECURITY_KRB_5_CREDENTIALS + ";");
      mv.visitInsn(RETURN);
      mv.visitMaxs(2, 2);
      mv.visitEnd();
    }
    cw.visitEnd();

    return cw.toByteArray();
  }
 

/**
 * Generate the class that encapsulates the compiled expression and define it.
 * The  generated class will be a subtype of CompiledExpression.
 *
 * @param expressionToCompile the expression to be compiled
 * @return the expression call, or {@code null} if the decision was to opt out of
 * compilation during code generation
 */
@SuppressWarnings("unchecked")
private Class<? extends CompiledExpression> createExpressionClass(SpelNodeImpl expressionToCompile) {
    // Create class outline 'spel/ExNNN extends org.springframework.expression.spel.CompiledExpression'
    String clazzName = "qunar/tc/bistoury/instrument/client/debugger/Ex" + getNextSuffix();
    ClassWriter cw = new ExpressionClassWriter();
    cw.visit(V1_5, ACC_PUBLIC, clazzName, null, "qunar/tc/bistoury/instrument/client/debugger/CompiledExpression", null);

    // Create default constructor
    MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
    mv.visitCode();
    mv.visitVarInsn(ALOAD, 0);
    mv.visitMethodInsn(INVOKESPECIAL, "qunar/tc/bistoury/instrument/client/debugger/CompiledExpression",
            "<init>", "()V", false);
    mv.visitInsn(RETURN);
    mv.visitMaxs(1, 1);
    mv.visitEnd();

    // Create getValue() method
    mv = cw.visitMethod(ACC_PUBLIC, "getValue",
            "(Ljava/lang/Object;Lqunar/tc/bistoury/instrument/client/debugger/EvaluationContext;)Ljava/lang/Object;", null,
            new String[]{"qunar/tc/bistoury/instrument/client/debugger/EvaluationException"});
    mv.visitCode();

    CodeFlow cf = new CodeFlow(clazzName, cw);

    // Ask the expression AST to generate the body of the method
    try {
        expressionToCompile.generateCode(mv, cf);
    } catch (IllegalStateException ex) {
        if (logger.isDebugEnabled()) {
            logger.debug(expressionToCompile.getClass().getSimpleName() +
                    ".generateCode opted out of compilation: " + ex.getMessage());
        }
        return null;
    }

    CodeFlow.insertBoxIfNecessary(mv, cf.lastDescriptor());
    if ("V".equals(cf.lastDescriptor())) {
        mv.visitInsn(ACONST_NULL);
    }
    mv.visitInsn(ARETURN);

    mv.visitMaxs(0, 0);  // not supplied due to COMPUTE_MAXS
    mv.visitEnd();
    cw.visitEnd();

    cf.finish();

    byte[] data = cw.toByteArray();
    // TODO need to make this conditionally occur based on a debug flag
    // dump(expressionToCompile.toStringAST(), clazzName, data);
    return (Class<? extends CompiledExpression>) this.ccl.defineClass(clazzName.replaceAll("/", "."), data);
}
 

public static byte[] dump() throws Exception {

		ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES);
		FieldVisitor fv;
		MethodVisitor mv;
		AnnotationVisitor av0;

		cw.visit(V1_6, ACC_PUBLIC + ACC_SUPER,
				"com/beetl/performance/lab/asm/UserAsmAccessor1", null,
				"java/lang/Object",
				new String[] { "com/beetl/performance/lab/asm/Access" });

		{
			mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
			mv.visitCode();
			mv.visitVarInsn(ALOAD, 0);
			mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>",
					"()V");
			mv.visitInsn(RETURN);
			mv.visitMaxs(1, 1);
			mv.visitEnd();
		}
		{
			mv = cw.visitMethod(
					ACC_PUBLIC,
					"get",
					"(Ljava/lang/Object;I)Ljava/lang/Object;",
					null,
					new String[] { "com/beetl/performance/lab/asm/ASMCastException" });
			mv.visitCode();
			Label l0 = new Label();
			Label l1 = new Label();
			Label l2 = new Label();
			mv.visitTryCatchBlock(l0, l1, l2, "java/lang/Exception");
			mv.visitInsn(ACONST_NULL);
			mv.visitVarInsn(ASTORE, 3);
			mv.visitLabel(l0);
			mv.visitVarInsn(ALOAD, 1);
			mv.visitTypeInsn(CHECKCAST, "com/beetl/performance/lab/User");
			mv.visitVarInsn(ASTORE, 3);
			mv.visitLabel(l1);
			Label l3 = new Label();
			mv.visitJumpInsn(GOTO, l3);
			mv.visitLabel(l2);
			mv.visitFrame(Opcodes.F_FULL, 4, new Object[] {
					"com/beetl/performance/lab/asm/UserAsmAccessor",
					"java/lang/Object", Opcodes.INTEGER,
					"com/beetl/performance/lab/User" }, 1,
					new Object[] { "java/lang/Exception" });
			mv.visitVarInsn(ASTORE, 4);
			mv.visitTypeInsn(NEW,
					"com/beetl/performance/lab/asm/ASMCastException");
			mv.visitInsn(DUP);
			mv.visitMethodInsn(INVOKESPECIAL,
					"com/beetl/performance/lab/asm/ASMCastException", "<init>",
					"()V");
			mv.visitInsn(ATHROW);
			mv.visitLabel(l3);
			mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
			mv.visitVarInsn(ILOAD, 2);
			Label l4 = new Label();
			Label l5 = new Label();
			Label l6 = new Label();
			mv.visitTableSwitchInsn(1, 2, l6, new Label[] { l4, l5 });
			mv.visitLabel(l4);
			mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
			mv.visitVarInsn(ALOAD, 3);
			mv.visitMethodInsn(INVOKEVIRTUAL, "com/beetl/performance/lab/User",
					"getName", "()Ljava/lang/String;");
			mv.visitInsn(ARETURN);
			mv.visitLabel(l5);
			mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
			mv.visitVarInsn(ALOAD, 3);
			mv.visitMethodInsn(INVOKEVIRTUAL, "com/beetl/performance/lab/User",
					"getId", "()I");
			mv.visitMethodInsn(INVOKESTATIC, "java/lang/Integer", "valueOf",
					"(I)Ljava/lang/Integer;");
			mv.visitInsn(ARETURN);
			mv.visitLabel(l6);
			mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
			mv.visitTypeInsn(NEW, "java/lang/RuntimeException");
			mv.visitInsn(DUP);
			mv.visitMethodInsn(INVOKESPECIAL, "java/lang/RuntimeException",
					"<init>", "()V");
			mv.visitInsn(ATHROW);
			mv.visitMaxs(2, 5);
			mv.visitEnd();
		}
		cw.visitEnd();

		return cw.toByteArray();
	}
 

public static byte[] dump() throws Exception {

		ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES);
		FieldVisitor fv;
		MethodVisitor mv;
		AnnotationVisitor av0;

		cw.visit(V1_6, ACC_PUBLIC + ACC_SUPER,
				"com/beetl/performance/lab/asm/UserAsmAccessor1", null,
				"java/lang/Object",
				new String[] { "com/beetl/performance/lab/asm/Access" });

		{
			mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
			mv.visitCode();
			mv.visitVarInsn(ALOAD, 0);
			mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>",
					"()V");
			mv.visitInsn(RETURN);
			mv.visitMaxs(1, 1);
			mv.visitEnd();
		}
		{
			mv = cw.visitMethod(
					ACC_PUBLIC,
					"get",
					"(Ljava/lang/Object;I)Ljava/lang/Object;",
					null,
					new String[] { "com/beetl/performance/lab/asm/ASMCastException" });
			mv.visitCode();
			Label l0 = new Label();
			Label l1 = new Label();
			Label l2 = new Label();
			mv.visitTryCatchBlock(l0, l1, l2, "java/lang/Exception");
			mv.visitInsn(ACONST_NULL);
			mv.visitVarInsn(ASTORE, 3);
			mv.visitLabel(l0);
			mv.visitVarInsn(ALOAD, 1);
			mv.visitTypeInsn(CHECKCAST, "com/beetl/performance/lab/User");
			mv.visitVarInsn(ASTORE, 3);
			mv.visitLabel(l1);
			Label l3 = new Label();
			mv.visitJumpInsn(GOTO, l3);
			mv.visitLabel(l2);
			mv.visitFrame(Opcodes.F_FULL, 4, new Object[] {
					"com/beetl/performance/lab/asm/UserAsmAccessor",
					"java/lang/Object", Opcodes.INTEGER,
					"com/beetl/performance/lab/User" }, 1,
					new Object[] { "java/lang/Exception" });
			mv.visitVarInsn(ASTORE, 4);
			mv.visitTypeInsn(NEW,
					"com/beetl/performance/lab/asm/ASMCastException");
			mv.visitInsn(DUP);
			mv.visitMethodInsn(INVOKESPECIAL,
					"com/beetl/performance/lab/asm/ASMCastException", "<init>",
					"()V");
			mv.visitInsn(ATHROW);
			mv.visitLabel(l3);
			mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
			mv.visitVarInsn(ILOAD, 2);
			Label l4 = new Label();
			Label l5 = new Label();
			Label l6 = new Label();
			mv.visitTableSwitchInsn(1, 2, l6, new Label[] { l4, l5 });
			mv.visitLabel(l4);
			mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
			mv.visitVarInsn(ALOAD, 3);
			mv.visitMethodInsn(INVOKEVIRTUAL, "com/beetl/performance/lab/User",
					"getName", "()Ljava/lang/String;");
			mv.visitInsn(ARETURN);
			mv.visitLabel(l5);
			mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
			mv.visitVarInsn(ALOAD, 3);
			mv.visitMethodInsn(INVOKEVIRTUAL, "com/beetl/performance/lab/User",
					"getId", "()I");
			mv.visitMethodInsn(INVOKESTATIC, "java/lang/Integer", "valueOf",
					"(I)Ljava/lang/Integer;");
			mv.visitInsn(ARETURN);
			mv.visitLabel(l6);
			mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
			mv.visitTypeInsn(NEW, "java/lang/RuntimeException");
			mv.visitInsn(DUP);
			mv.visitMethodInsn(INVOKESPECIAL, "java/lang/RuntimeException",
					"<init>", "()V");
			mv.visitInsn(ATHROW);
			mv.visitMaxs(2, 5);
			mv.visitEnd();
		}
		cw.visitEnd();

		return cw.toByteArray();
	}
 

private static byte[] generateInterfaceBytecode(String wrapperInterfaceSlashName, String[] superInterfaces) {
    ClassWriter classWriter = new ClassWriter(ClassWriter.COMPUTE_MAXS);
    classWriter.visit(V10, ACC_PUBLIC | ACC_ABSTRACT | ACC_INTERFACE , wrapperInterfaceSlashName, null, "java/lang/Object", superInterfaces);
    classWriter.visitEnd();
    return classWriter.toByteArray();
}
 

public static byte[] makeExample() throws Throwable {
	      ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES);
	      cw.visit(V1_7, ACC_PUBLIC | ACC_SUPER, "ComplexIndy", null, "java/lang/Object", null);
	      		      
	      MethodVisitor mv;
	      {
	         mv = cw.visitMethod(ACC_PUBLIC | ACC_STATIC, "gwtTest", "(Ljava/lang/Object;)Ljava/lang/String;", null, null);
	         mv.visitCode();
		 mv.visitVarInsn(ALOAD, 0);
	         mv.visitInvokeDynamicInsn("gwtBootstrap", "(Ljava/lang/Object;)Ljava/lang/String;",
	               new Handle(
	            		   H_INVOKESTATIC, 
	            		   "BootstrapMethods", 
	            		   "fibBootstrap",
	            		   Type.getType(
	            				 "(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite;"
	            		   ).getDescriptor())
	         );
	         mv.visitInsn(ARETURN);
	         mv.visitMaxs(0, 0);
	         mv.visitEnd();
	      }

	{
		mv = cw.visitMethod(ACC_PUBLIC | ACC_STATIC, "fibIndy", "(I)I", null, null);
		mv.visitCode();
		mv.visitVarInsn(ILOAD, 0);
		mv.visitInvokeDynamicInsn("fibBootstrap", "(I)I",
			new Handle(
				H_INVOKESTATIC, 
				"BootstrapMethods", 
				"fibBootstrap",
				Type.getType(
					"(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite;"
				).getDescriptor())
			);
		mv.visitInsn(IRETURN);
		mv.visitMaxs(0, 0);
		mv.visitEnd();
	}
cw.visitEnd();
return cw.toByteArray();
}
 

public static void main(String[] args) throws IOException {
  ClassWriter writer = new ClassWriter(COMPUTE_MAXS|COMPUTE_MAXS);
  
  // reserve slot 1 of the constant pool (see LoggerServiceSPI)
  writer.newClass("com/github/forax/beautifullogger/Logger");
  
  writer.visit(V1_8, ACC_SUPER,
      "com/github/forax/beautifullogger/Logger$Stub", null,
      "java/lang/Object",
      new String[] {"com/github/forax/beautifullogger/Logger"});
  
  // field
  writer.visitField(ACC_PRIVATE|ACC_FINAL, "mh", "Ljava/lang/invoke/MethodHandle;", null, null);
  
  // constructor
  MethodVisitor init = writer.visitMethod(ACC_PRIVATE, "<init>", "(Ljava/lang/invoke/MethodHandle;)V", null, null);
  init.visitCode();
  init.visitVarInsn(ALOAD, 0);
  init.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);
  init.visitVarInsn(ALOAD, 0);
  init.visitVarInsn(ALOAD, 1);
  init.visitFieldInsn(PUTFIELD, "com/github/forax/beautifullogger/Logger$Stub", "mh", "Ljava/lang/invoke/MethodHandle;");
  init.visitInsn(RETURN);
  init.visitMaxs(0, 0);
  init.visitEnd();
  
  // static factory method
  MethodVisitor factory = writer.visitMethod(ACC_PUBLIC|ACC_STATIC, "create",
      "(Ljava/lang/invoke/MethodHandle;)Lcom/github/forax/beautifullogger/Logger;", null, null);
  factory.visitCode();
  factory.visitTypeInsn(NEW, "com/github/forax/beautifullogger/Logger$Stub");
  factory.visitInsn(DUP);
  factory.visitVarInsn(ALOAD, 0);
  factory.visitMethodInsn(INVOKESPECIAL, "com/github/forax/beautifullogger/Logger$Stub", "<init>",
      "(Ljava/lang/invoke/MethodHandle;)V", false);
  factory.visitInsn(ARETURN);
  factory.visitMaxs(0, 0);
  factory.visitEnd();
  
  // method
  generateOverride(writer,
      Paths.get("target/main/exploded/com.github.forax.beautifullogger/com/github/forax/beautifullogger/Logger.class"));
  generateOverride(writer,
      Paths.get("target/main/exploded/com.github.forax.beautifullogger/com/github/forax/beautifullogger/LogService.class"));
  
  writer.visitEnd();
  
  byte[] array = writer.toByteArray();
  
  //DEBUG
  //Files.write(Paths.get("Logger$Stub.class"), array);
  
  String data = new String(Base64.getEncoder().encode(array), ISO_8859_1);
  System.out.println(data);
}
 

private <T extends Script> Class<? extends T> generateEmptyScriptClass(Class<T> type) {
    ClassWriter visitor = new ClassWriter(ClassWriter.COMPUTE_MAXS);
    String typeName = type.getName() + "_Decorated";
    Type generatedType = Type.getType("L" + typeName.replaceAll("\\.", "/") + ";");
    Type superclassType = Type.getType(type);
    visitor.visit(Opcodes.V1_5, Opcodes.ACC_PUBLIC, generatedType.getInternalName(), null,
            superclassType.getInternalName(), new String[0]);

    // Constructor

    String constructorDescriptor = Type.getMethodDescriptor(Type.VOID_TYPE, new Type[0]);
    MethodVisitor methodVisitor = visitor.visitMethod(Opcodes.ACC_PUBLIC, "<init>", constructorDescriptor, null,
            new String[0]);
    methodVisitor.visitCode();

    // super()
    methodVisitor.visitVarInsn(Opcodes.ALOAD, 0);
    methodVisitor.visitMethodInsn(Opcodes.INVOKESPECIAL, superclassType.getInternalName(), "<init>",
            constructorDescriptor);

    methodVisitor.visitInsn(Opcodes.RETURN);
    methodVisitor.visitMaxs(0, 0);
    methodVisitor.visitEnd();

    // run() method

    String runDesciptor = Type.getMethodDescriptor(Type.getType(Object.class), new Type[0]);
    methodVisitor = visitor.visitMethod(Opcodes.ACC_PUBLIC, "run", runDesciptor, null, new String[0]);
    methodVisitor.visitCode();

    // return null
    methodVisitor.visitInsn(Opcodes.ACONST_NULL);

    methodVisitor.visitInsn(Opcodes.ARETURN);
    methodVisitor.visitMaxs(0, 0);
    methodVisitor.visitEnd();

    visitor.visitEnd();

    byte[] bytecode = visitor.toByteArray();
    JavaMethod<ClassLoader, Class> method = JavaReflectionUtil.method(ClassLoader.class, Class.class, "defineClass", String.class, byte[].class, int.class, int.class);
    @SuppressWarnings("unchecked")
    Class<T> clazz = method.invoke(type.getClassLoader(), typeName, bytecode, 0, bytecode.length);
    return clazz;
}
 

public static void assembleMethodHandleField(final ClassWriter cw, final Method targetMethod, final String invokerName) {
    final String desc = Type.getDescriptor(MethodHandle.class);
    cw.visitField(ACC_PRIVATE | ACC_FINAL + ACC_STATIC, "HANDLE", desc, null, null);
    cw.visitEnd();

    final MethodVisitor ctor = cw.visitMethod(ACC_STATIC, "<clinit>", "()V", null, null);
    final Label cs = createLabel();
    final Label ce = createLabel();

    ctor.visitCode();
    ctor.visitLabel(cs);

    final String clName = targetMethod.getDeclaringClass().getCanonicalName();
    final String targetMethodName = targetMethod.getName();
    ctor.visitLdcInsn(clName);
    ctor.visitLdcInsn(targetMethodName);

    final Parameter[] parameters = targetMethod.getParameters();
    ctor.visitLdcInsn(parameters.length);

    final Type classType = Type.getType(Class.class);
    final String descriptor = classType.getInternalName();
    ctor.visitTypeInsn(ANEWARRAY, descriptor);

    for (int i = 0; i < parameters.length; i++) {
        ctor.visitInsn(DUP);
        ctor.visitLdcInsn(i);

        final Class<?> paramClass = parameters[i].getType();
        if (paramClass.isPrimitive()) {
            final Class<?> wrapper = Primitives.wrap(paramClass);
            final String holderName = Type.getType(wrapper).getInternalName();

            ctor.visitFieldInsn(GETSTATIC, holderName, "TYPE", CL_DESCRIPTOR);
        } else {
            final Type parameterType = Type.getType(paramClass);
            ctor.visitLdcInsn(parameterType);
        }

        ctor.visitInsn(AASTORE);
    }

    ctor.visitMethodInsn(INVOKESTATIC, MHC_INTERNAL_NAME, "createUniversal",
            '(' + STR_DESCRIPTOR + STR_DESCRIPTOR + CLA_DESCRIPTOR + ')' + MH_DESCRIPTOR, false);
    ctor.visitFieldInsn(PUTSTATIC, invokerName, "HANDLE", MH_DESCRIPTOR);
    ctor.visitInsn(RETURN);

    ctor.visitLabel(ce);
    ctor.visitEnd();

    ctor.visitMaxs(0, 0);
}