Java Code Examples for jdk.internal.org.objectweb.asm.MethodVisitor#visitEnd()

public static void writeClassFile() throws Exception {
    ClassWriter cw = new ClassWriter(0);
    MethodVisitor mv;

    cw.visit(99, ACC_PUBLIC + ACC_SUPER, "ClassFile", null, "java/lang/Object", null);
    mv = cw.visitMethod(ACC_PUBLIC, "<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();
    cw.visitEnd();

    try (FileOutputStream fos = new FileOutputStream(new File("ClassFile.class"))) {
         fos.write(cw.toByteArray());
    }
}
 

void addConstructor(BinderClassWriter cw) {
    MethodType constrType = MethodType.methodType(void.class, VarForm.class, boolean.class, long.class, long.class, long.class, long[].class);
    MethodVisitor mv = cw.visitMethod(0, "<init>", constrType.toMethodDescriptorString(), null, null);
    mv.visitCode();
    //super call
    mv.visitVarInsn(ALOAD, 0);
    mv.visitVarInsn(ALOAD, 1);
    mv.visitTypeInsn(CHECKCAST, Type.getInternalName(VarForm.class));
    mv.visitVarInsn(ILOAD, 2);
    mv.visitVarInsn(LLOAD, 3);
    mv.visitVarInsn(LLOAD, 5);
    mv.visitVarInsn(LLOAD, 7);
    mv.visitMethodInsn(INVOKESPECIAL, Type.getInternalName(BASE_CLASS), "<init>",
            MethodType.methodType(void.class, VarForm.class, boolean.class, long.class, long.class, long.class).toMethodDescriptorString(), false);
    //init dimensions
    for (int i = 0 ; i < dimensions ; i++) {
        mv.visitVarInsn(ALOAD, 0);
        mv.visitVarInsn(ALOAD, 9);
        mv.visitLdcInsn(i);
        mv.visitInsn(LALOAD);
        mv.visitFieldInsn(PUTFIELD, implClassName, "dim" + i, "J");
    }
    mv.visitInsn(RETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();
}
 

/**
 * The bytes for D, a NOT abstract class extending abstract class C without
 * supplying an implementation for abstract method m. There is a default
 * method in the interface I, but it should lose to the abstract class.
 *
 * @return
 * @throws Exception
 */
public static byte[] bytesForD() throws Exception {

    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES
            | ClassWriter.COMPUTE_MAXS);
    MethodVisitor mv;

    cw.visit(V1_8, ACC_PUBLIC + ACC_SUPER, "p/D", null, "p/C", null);

    {
        mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
        mv.visitCode();
        mv.visitVarInsn(ALOAD, 0);
        mv.visitMethodInsn(INVOKESPECIAL, "p/C", "<init>", "()V");
        mv.visitInsn(RETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }
    cw.visitEnd();

    return cw.toByteArray();
}
 

public static void writeClassFile() throws Exception {
    ClassWriter cw = new ClassWriter(0);
    MethodVisitor mv;

    cw.visit(99, ACC_PUBLIC + ACC_SUPER, "ClassFile", null, "java/lang/Object", null);
    mv = cw.visitMethod(ACC_PUBLIC, "<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();
    cw.visitEnd();

    try (FileOutputStream fos = new FileOutputStream(new File("ClassFile.class"))) {
         fos.write(cw.toByteArray());
    }
}
 

/**
 * The bytes for D, a NOT abstract class extending abstract class C without
 * supplying an implementation for abstract method m. There is a default
 * method in the interface I, but it should lose to the abstract class.
 *
 * @return
 * @throws Exception
 */
public static byte[] bytesForD() throws Exception {

    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES
            | ClassWriter.COMPUTE_MAXS);
    MethodVisitor mv;

    cw.visit(V1_8, ACC_PUBLIC + ACC_SUPER, "p/D", null, "p/C", null);

    {
        mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
        mv.visitCode();
        mv.visitVarInsn(ALOAD, 0);
        mv.visitMethodInsn(INVOKESPECIAL, "p/C", "<init>", "()V");
        mv.visitInsn(RETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }
    cw.visitEnd();

    return cw.toByteArray();
}
 

/**
 * The bytes for D, a NOT abstract class extending abstract class C without
 * supplying an implementation for abstract method m. There is a default
 * method in the interface I, but it should lose to the abstract class.
 *
 * @return
 * @throws Exception
 */
public static byte[] bytesForD() throws Exception {

    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES
            | ClassWriter.COMPUTE_MAXS);
    MethodVisitor mv;

    cw.visit(V1_8, ACC_PUBLIC + ACC_SUPER, "p/D", null, "p/C", null);

    {
        mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
        mv.visitCode();
        mv.visitVarInsn(ALOAD, 0);
        mv.visitMethodInsn(INVOKESPECIAL, "p/C", "<init>", "()V");
        mv.visitInsn(RETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }
    cw.visitEnd();

    return cw.toByteArray();
}
 

public static void main(String[] args) throws NoSuchMethodException,SecurityException,
        IllegalAccessException,IllegalArgumentException,InvocationTargetException{
    ClassWriter cw=new ClassWriter(ClassWriter.COMPUTE_MAXS|ClassWriter.COMPUTE_FRAMES);
    cw.visit(V1_7,ACC_PUBLIC,"Example",null,"java/lang/Object",null);
    MethodVisitor mw=cw.visitMethod(ACC_PUBLIC,"<init>","()V",null,null);
    mw.visitVarInsn(ALOAD,0);
    mw.visitMethodInsn(INVOKESPECIAL,"java/lang/Object","<init>","()V");
    mw.visitInsn(RETURN);
    mw.visitMaxs(0,0);
    mw.visitEnd();
    mw=cw.visitMethod(ACC_PUBLIC+ACC_STATIC,"main","([Ljava/lang/String;)V",null,null);
    mw.visitFieldInsn(GETSTATIC,"java/lang/System","out","Ljava/io/PrintStream;");
    mw.visitLdcInsn("Hello world!");
    mw.visitMethodInsn(INVOKEVIRTUAL,"java/io/PrintStream","println","(Ljava/lang/String;)V");
    mw.visitInsn(RETURN);
    mw.visitMaxs(0,0);
    mw.visitEnd();
    byte[] code=cw.toByteArray();
    for(int i=0;i<1;i++){
        ClassLoader loader=UnloadClass.class.getClassLoader();
        Method m=ClassLoader.class.getDeclaredMethod("defineClass", String.class, byte[].class, int.class, int.class);
        m.setAccessible(true);
        m.invoke(loader,"Example",code,0,code.length);
        m.setAccessible(false);
        System.gc();
    }

}
 

/**
 * Generate a class file with the given class name. The class implements Runnable
 * with a run method to invokestatic the given targetClass/targetMethod.
 */
byte[] generateRunner(String className,
                      String targetClass,
                      String targetMethod) throws Exception {

    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS
                                     + ClassWriter.COMPUTE_FRAMES);
    cw.visit(V1_9,
            ACC_PUBLIC + ACC_SUPER,
            className.replace(".", "/"),
            null,
            "java/lang/Object",
            new String[] { "java/lang/Runnable" });

    // <init>
    MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
    mv.visitVarInsn(ALOAD, 0);
    mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);
    mv.visitInsn(RETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();

    // run()
    String tc = targetClass.replace(".", "/");
    mv = cw.visitMethod(ACC_PUBLIC, "run", "()V", null, null);
    mv.visitMethodInsn(INVOKESTATIC, tc, targetMethod, "()V", false);
    mv.visitInsn(RETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();

    cw.visitEnd();
    return cw.toByteArray();
}
 

private byte[] loadClassData(String name) throws Exception {
    ClassWriter cw = new ClassWriter(0);
    MethodVisitor mv;
    switch (name) {
        case INTERFACE_NAME:
            cw.visit(V1_8, ACC_ABSTRACT | ACC_INTERFACE | ACC_PUBLIC, INTERFACE_NAME, null, "java/lang/Object", null);
            {
                mv = cw.visitMethod(ACC_PRIVATE, "privInstance", "()I", null, null);
                mv.visitCode();
                mv.visitLdcInsn(EXPECTED);
                mv.visitInsn(IRETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();
            }
            break;
        case CLASS_NAME:
            cw.visit(52, ACC_SUPER | ACC_PUBLIC, CLASS_NAME, null, "java/lang/Object", new String[]{INTERFACE_NAME});
            {
                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();
            }
            break;
        default:
            break;
    }
    cw.visitEnd();

    return cw.toByteArray();
}
 

private byte[] loadClassData(String name) throws Exception {
    ClassWriter cw = new ClassWriter(0);
    MethodVisitor mv;
    switch (name) {
        case INTERFACE_NAME:
            cw.visit(V1_8, ACC_ABSTRACT | ACC_INTERFACE | ACC_PUBLIC, INTERFACE_NAME, null, "java/lang/Object", null);
            {
                mv = cw.visitMethod(ACC_PRIVATE, "privInstance", "()I", null, null);
                mv.visitCode();
                mv.visitLdcInsn(EXPECTED);
                mv.visitInsn(IRETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();
            }
            break;
        case CLASS_NAME:
            cw.visit(52, ACC_SUPER | ACC_PUBLIC, CLASS_NAME, null, "java/lang/Object", new String[]{INTERFACE_NAME});
            {
                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();
            }
            break;
        default:
            break;
    }
    cw.visitEnd();

    return cw.toByteArray();
}
 

private byte[] loadClassData(String name) throws Exception {
    ClassWriter cw = new ClassWriter(0);
    MethodVisitor mv;
    switch (name) {
        case INTERFACE_NAME:
            cw.visit(V1_8, ACC_ABSTRACT | ACC_INTERFACE | ACC_PUBLIC, INTERFACE_NAME, null, "java/lang/Object", null);
            {
                mv = cw.visitMethod(ACC_PRIVATE, "privInstance", "()I", null, null);
                mv.visitCode();
                mv.visitLdcInsn(EXPECTED);
                mv.visitInsn(IRETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();
            }
            break;
        case CLASS_NAME:
            cw.visit(52, ACC_SUPER | ACC_PUBLIC, CLASS_NAME, null, "java/lang/Object", new String[]{INTERFACE_NAME});
            {
                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();
            }
            break;
        default:
            break;
    }
    cw.visitEnd();

    return cw.toByteArray();
}
 

private void buildConstructor() {
    MethodVisitor mv = classWriter.visitMethod(Opcodes.ACC_PRIVATE, METHOD_EVENT_HANDLER_CONSTRUCTOR.getName(), makeConstructorDescriptor(settingInfos), null, null);
    mv.visitVarInsn(Opcodes.ALOAD, 0); // this
    mv.visitVarInsn(Opcodes.ILOAD, 1); // registered
    mv.visitVarInsn(Opcodes.ALOAD, 2); // event type
    mv.visitVarInsn(Opcodes.ALOAD, 3); // event control
    mv.visitMethodInsn(Opcodes.INVOKESPECIAL, Type.getInternalName(EventHandler.class), METHOD_EVENT_HANDLER_CONSTRUCTOR.getName(), METHOD_EVENT_HANDLER_CONSTRUCTOR.getDescriptor(), false);
    for (SettingInfo si : settingInfos) {
        mv.visitVarInsn(Opcodes.ALOAD, 0); // this
        mv.visitVarInsn(Opcodes.ALOAD, si.index + 4); // Setting Control
        mv.visitFieldInsn(Opcodes.PUTFIELD, internalClassName, si.fieldName, TYPE_SETTING_CONTROL.getDescriptor());
    }
    // initialized string field writers
    int fieldIndex = 0;
    for (FieldInfo field : fields) {
        if (field.isString()) {
            mv.visitVarInsn(Opcodes.ALOAD, 0);
            mv.visitVarInsn(Opcodes.ALOAD, 0);
            mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, Type.getInternalName(EventHandler.class), "createStringFieldWriter", "()" + TYPE_STRING_POOL.getDescriptor(), false);
            mv.visitFieldInsn(Opcodes.PUTFIELD, internalClassName, FIELD_PREFIX_STRING_POOL + fieldIndex, TYPE_STRING_POOL.getDescriptor());
        }
        fieldIndex++;
    }
    mv.visitInsn(Opcodes.RETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();
}
 

/**
 * Generate bytecode for SystemModules::targets method
 */
private void genTargetsMethod() {
    MethodVisitor mv = cw.visitMethod(ACC_PUBLIC+ACC_STATIC,
                                      "targets",
                                      "()" + MODULE_TARGET_ARRAY_SIGNATURE,
                                      "()" + MODULE_TARGET_ARRAY_SIGNATURE,
                                      null);
    mv.visitCode();
    pushInt(mv, moduleInfos.size());
    mv.visitTypeInsn(ANEWARRAY, MODULE_TARGET_CLASSNAME);
    mv.visitVarInsn(ASTORE, MT_VAR);

    for (int index=0; index < moduleInfos.size(); index++) {
        ModuleInfo minfo = moduleInfos.get(index);
        if (minfo.target() != null && !minfo.dropModuleTarget) {
            mv.visitVarInsn(ALOAD, MT_VAR);
            pushInt(mv, index);

            // new ModuleTarget(String, String)
            mv.visitTypeInsn(NEW, MODULE_TARGET_CLASSNAME);
            mv.visitInsn(DUP);
            mv.visitLdcInsn(minfo.target().targetPlatform());
            mv.visitMethodInsn(INVOKESPECIAL, MODULE_TARGET_CLASSNAME,
                "<init>", "(Ljava/lang/String;)V", false);

            mv.visitInsn(AASTORE);
        }
    }

    mv.visitVarInsn(ALOAD, MT_VAR);
    mv.visitInsn(ARETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();
}
 

private static void buildDurationMethod() {
    MethodVisitor mv = classWriter.visitMethod(Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC, METHOD_DURATION.getName(), METHOD_DURATION.getDescriptor(), null, null);
    mv.visitCode();
    mv.visitVarInsn(Opcodes.LLOAD, 0);
    mv.visitMethodInsn(Opcodes.INVOKESTATIC, Type.getInternalName(EventHandler.class), METHOD_DURATION.getName(), METHOD_DURATION.getDescriptor(), false);
    mv.visitInsn(Opcodes.LRETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();
}
 

private byte[] loadClassData(String name) throws Exception {
  ClassWriter cw = new ClassWriter(0);
  MethodVisitor mv;

  if (name.equals("C")) {
    cw.visit(52, ACC_SUPER | ACC_PUBLIC, "C", null, "java/lang/Object", null);
    {
      mv = cw.visitMethod(ACC_PRIVATE | ACC_STATIC, "m", "()V", null, null);
      mv.visitCode();
      mv.visitInsn(RETURN);
      mv.visitMaxs(0, 1);
      mv.visitEnd();
    }
    cw.visitEnd();
    return cw.toByteArray();
  } else if (name.equals("Exec")) {
    cw.visit(52, ACC_SUPER | ACC_PUBLIC, "Exec", null, "java/lang/Object", null);
    {
      mv = cw.visitMethod(ACC_PUBLIC | ACC_STATIC, "invokeRef", "()V", null, null);
      mv.visitCode();
      Handle h = new Handle(H_INVOKESTATIC, "C", "m", "()V");
      mv.visitInvokeDynamicInsn("C", "()V", h);
      mv.visitInsn(RETURN);
      mv.visitMaxs(0, 0);
      mv.visitEnd();
    }
    cw.visitEnd();
    return cw.toByteArray();
  }
  return null;
}
 

private void buildConstructor() {
    MethodVisitor mv = classWriter.visitMethod(Opcodes.ACC_PRIVATE, METHOD_EVENT_HANDLER_CONSTRUCTOR.getName(), makeConstructorDescriptor(settingInfos), null, null);
    mv.visitVarInsn(Opcodes.ALOAD, 0); // this
    mv.visitVarInsn(Opcodes.ILOAD, 1); // registered
    mv.visitVarInsn(Opcodes.ALOAD, 2); // event type
    mv.visitVarInsn(Opcodes.ALOAD, 3); // event control
    mv.visitMethodInsn(Opcodes.INVOKESPECIAL, Type.getInternalName(eventHandlerProxy), METHOD_EVENT_HANDLER_CONSTRUCTOR.getName(), METHOD_EVENT_HANDLER_CONSTRUCTOR.getDescriptor(), false);
    for (SettingInfo si : settingInfos) {
        mv.visitVarInsn(Opcodes.ALOAD, 0); // this
        mv.visitVarInsn(Opcodes.ALOAD, si.index + 4); // Setting Control
        mv.visitFieldInsn(Opcodes.PUTFIELD, internalClassName, si.fieldName, TYPE_SETTING_CONTROL.getDescriptor());
    }
    // initialized string field writers
    int fieldIndex = 0;
    for (FieldInfo field : fields) {
        if (field.isString()) {
            mv.visitVarInsn(Opcodes.ALOAD, 0);
            mv.visitVarInsn(Opcodes.ALOAD, 0);
            mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, Type.getInternalName(eventHandlerProxy), "createStringFieldWriter", "()" + TYPE_STRING_POOL.getDescriptor(), false);
            mv.visitFieldInsn(Opcodes.PUTFIELD, internalClassName, FIELD_PREFIX_STRING_POOL + fieldIndex, TYPE_STRING_POOL.getDescriptor());
        }
        fieldIndex++;
    }
    mv.visitInsn(Opcodes.RETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();
}
 

/**
 * Generate bytecode for SystemModules::methodResoultions method
 */
private void genModuleResolutionsMethod() {
    MethodVisitor mresmv =
        cw.visitMethod(ACC_PUBLIC+ACC_STATIC,
                       "moduleResolutions",
                       "()" + MODULE_RESOLUTIONS_ARRAY_SIGNATURE,
                       "()" + MODULE_RESOLUTIONS_ARRAY_SIGNATURE,
                       null);
    mresmv.visitCode();
    pushInt(mresmv, moduleInfos.size());
    mresmv.visitTypeInsn(ANEWARRAY, MODULE_RESOLUTION_CLASSNAME);
    mresmv.visitVarInsn(ASTORE, 0);

    for (int index=0; index < moduleInfos.size(); index++) {
        ModuleInfo minfo = moduleInfos.get(index);
        if (minfo.moduleResolution() != null) {
            mresmv.visitVarInsn(ALOAD, 0);
            pushInt(mresmv, index);
            mresmv.visitTypeInsn(NEW, MODULE_RESOLUTION_CLASSNAME);
            mresmv.visitInsn(DUP);
            mresmv.visitLdcInsn(minfo.moduleResolution().value());
            mresmv.visitMethodInsn(INVOKESPECIAL,
                                   MODULE_RESOLUTION_CLASSNAME,
                                   "<init>",
                                   "(I)V", false);
            mresmv.visitInsn(AASTORE);
        }
    }
    mresmv.visitVarInsn(ALOAD, 0);
    mresmv.visitInsn(ARETURN);
    mresmv.visitMaxs(0, 0);
    mresmv.visitEnd();
}
 

/**
 * Returns the bytes for a class with name d_name (presumably "D" in some
 * package), extending some class with name sub_what, implementing p.I,
 * and defining two methods m() and m(11args) with access method_acc.
 *
 * @param d_name      Name of class that is defined
 * @param sub_what    Name of class that it extends
 * @param method_acc  Accessibility of method(s) m in defined class.
 * @return
 * @throws Exception
 */
public static byte[] bytesForSomeDsubSomethingSomeAccess
        (String d_name, String sub_what, int method_acc)
        throws Exception {

    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES
            | ClassWriter.COMPUTE_MAXS);
    MethodVisitor mv;
    String[] interfaces = {"p/I"};

    cw.visit(V1_8, ACC_PUBLIC + ACC_SUPER, d_name, null, sub_what, interfaces);
    {
        mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
        mv.visitCode();
        mv.visitVarInsn(ALOAD, 0);
        mv.visitMethodInsn(INVOKESPECIAL, sub_what, "<init>", "()V");
        mv.visitInsn(RETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }
    // int m() {return 3;}
    {
        mv = cw.visitMethod(method_acc, "m", "()I", null, null);
        mv.visitCode();
        mv.visitLdcInsn(new Integer(3));
        mv.visitInsn(IRETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }
    // int m(11args) {return 3;}
    {
        mv = cw.visitMethod(method_acc, "m", "(BCSIJ"
                + "Ljava/lang/Object;"
                + "Ljava/lang/Object;"
                + "Ljava/lang/Object;"
                + "Ljava/lang/Object;"
                + "Ljava/lang/Object;"
                + "Ljava/lang/Object;"
                + ")I", null, null);
        mv.visitCode();
        mv.visitLdcInsn(new Integer(3));
        mv.visitInsn(IRETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }
    cw.visitEnd();
    return cw.toByteArray();
}
 

/**
 * Test a service provider that defines more than one no-args
 * public static "provider" method.
 */
@Test(expectedExceptions = ServiceConfigurationError.class)
public void testWithTwoFactoryMethods() throws Exception {
    Path mods = compileTest(TEST1_MODULE);

    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS
                                     + ClassWriter.COMPUTE_FRAMES);
    cw.visit(V1_9,
            ACC_PUBLIC + ACC_SUPER,
            "p/ProviderFactory",
            null,
            "java/lang/Object",
            null);

    // public static p.Service provider()
    MethodVisitor mv = cw.visitMethod(ACC_PUBLIC + ACC_STATIC,
            "provider",
            "()Lp/Service;",
            null,
            null);
    mv.visitTypeInsn(NEW, "p/ProviderFactory$1");
    mv.visitInsn(DUP);
    mv.visitMethodInsn(INVOKESPECIAL,
            "p/ProviderFactory$1",
            "<init>", "()V",
            false);
    mv.visitInsn(ARETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();

    // public static p.ProviderFactory$1 provider()
    mv = cw.visitMethod(ACC_PUBLIC + ACC_STATIC,
            "provider",
            "()Lp/ProviderFactory$1;",
            null,
            null);
    mv.visitTypeInsn(NEW, "p/ProviderFactory$1");
    mv.visitInsn(DUP);
    mv.visitMethodInsn(INVOKESPECIAL,
            "p/ProviderFactory$1",
            "<init>",
            "()V",
            false);
    mv.visitInsn(ARETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();

    cw.visitEnd();

    // write the class bytes into the compiled module directory
    Path classFile = mods.resolve(TEST1_MODULE)
            .resolve("p")
            .resolve("ProviderFactory.class");
    Files.write(classFile, cw.toByteArray());

    // load providers and instantiate each one
    loadProviders(mods, TEST1_MODULE).forEach(Provider::get);
}
 

private byte[] loadClassData(String name) throws Exception {
    ClassWriter cw = new ClassWriter(0);
    MethodVisitor mv;
    switch (name) {
       case CLASS_NAME_A:
            cw.visit(52, ACC_SUPER | ACC_PUBLIC, CLASS_NAME_A, null, "java/lang/Object", null);
            {
                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_FINAL | ACC_STATIC, "m", "()I", null, null);
                mv.visitCode();
                mv.visitLdcInsn(FAILED);
                mv.visitInsn(IRETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();
            }
            break;
        case CLASS_NAME_B:
            cw.visit(52, ACC_SUPER | ACC_PUBLIC, CLASS_NAME_B, null, CLASS_NAME_A, null);
            {
                mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
                mv.visitCode();
                mv.visitVarInsn(ALOAD, 0);
                mv.visitMethodInsn(INVOKESPECIAL, CLASS_NAME_A, "<init>", "()V");
                mv.visitInsn(RETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();

                mv = cw.visitMethod(ACC_PUBLIC, "m", "()I", null, null);
                mv.visitCode();
                mv.visitLdcInsn(EXPECTED);
                mv.visitInsn(IRETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();

            }
            break;
        default:
            break;
    }
    cw.visitEnd();

    return cw.toByteArray();
}