Program: 161307
Project: 161307
Buggy source:
@Override public void onLoad(ClassPool pool,String name) throws NotFoundException, CannotCompileException {
  CtClass clazz=pool.get(name);
  clazz.setModifiers(clazz.getModifiers() & ~Modifier.FINAL);
  for (  CtMethod method : clazz.getDeclaredMethods()) {
    method.setModifiers(method.getModifiers() & ~Modifier.FINAL);
  }
  for (  CtMethod method : clazz.getDeclaredMethods()) {
    if (shouldStubMethod(method)) {
      method.setModifiers(method.getModifiers() & ~Modifier.NATIVE);
      CtClass returnType=method.getReturnType();
      if (typeIs(returnType,String.class)) {
        method.setBody("String_Node_Str");
      }
 else       if (typeIs(returnType,Boolean.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (typeIs(returnType,Byte.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (typeIs(returnType,Character.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (typeIs(returnType,Double.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (typeIs(returnType,Integer.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (typeIs(returnType,Float.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (typeIs(returnType,Long.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (typeIs(returnType,Short.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (returnType.isPrimitive()) {
        method.setBody(null);
      }
 else       if (returnType.isEnum()) {
        method.setBody(String.format("String_Node_Str",returnType.getName()));
      }
 else {
        method.setBody(String.format("String_Node_Str" + "String_Node_Str",returnType.getName()));
      }
    }
  }
  for (  Class<?> classToStub : getClassesToStub()) {
    if (classToStub.getName().equals(clazz.getName())) {
      for (      CtConstructor constructor : clazz.getConstructors()) {
        String parameters=makeNullParameters(clazz.getSuperclass().getConstructors()[0].getParameterTypes().length);
        constructor.setBody("String_Node_Str" + parameters + "String_Node_Str");
      }
    }
  }
}

Fixed version (ground truth):
@Override public void onLoad(ClassPool pool,String name) throws NotFoundException, CannotCompileException {
  CtClass clazz=pool.get(name);
  clazz.setModifiers(clazz.getModifiers() & ~Modifier.FINAL);
  for (  CtMethod method : clazz.getDeclaredMethods()) {
    method.setModifiers(method.getModifiers() & ~Modifier.FINAL);
  }
  for (  CtMethod method : clazz.getDeclaredMethods()) {
    if (shouldStubMethod(method)) {
      method.setModifiers(method.getModifiers() & ~Modifier.NATIVE);
      CtClass returnType=method.getReturnType();
      if (typeIs(returnType,String.class)) {
        method.setBody("String_Node_Str");
      }
 else       if (typeIs(returnType,Boolean.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (typeIs(returnType,Byte.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (typeIs(returnType,Character.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (typeIs(returnType,Double.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (typeIs(returnType,Integer.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (typeIs(returnType,Float.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (typeIs(returnType,Long.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (typeIs(returnType,Short.class)) {
        method.setBody(String.format("String_Node_Str"));
      }
 else       if (returnType.isPrimitive()) {
        method.setBody(null);
      }
 else       if (returnType.isEnum()) {
        method.setBody(String.format("String_Node_Str",returnType.getName()));
      }
 else {
        method.setBody(String.format("String_Node_Str" + "String_Node_Str",returnType.getName()));
      }
    }
  }
  for (  Class<?> classToStub : getClassesToStub()) {
    if (classToStub.getName().equals(clazz.getName())) {
      for (      CtConstructor constructor : clazz.getConstructors()) {
        String parameters=makeNullParameters(clazz.getSuperclass().getConstructors()[0].getParameterTypes());
        constructor.setBody("String_Node_Str" + parameters + "String_Node_Str");
      }
    }
  }
}