Anonymous Inner Class Issue in Javassist generated class

Question

I am using Javassist to generate some classes at runtime and when I make anonymous inner classes in these classes they crash upon trying to instantiate an enclosing object (as far as I can tell)

I have tried to implement the simplest version of what I am trying to do.

I define 3 classes as follows:

public class A {

    public int method() {
        return 1;
    }
}

public class B extends A {

}

public class C extends A {
    public int method() {
        return 5;
    }
}

What I want to do now is use javassist (or something else I guess) to (at runtime) generate a class that has all of the functionality of C but that extends B instead of A, to me this seems like a thing that would be fine, since B extends A. Currently I am doing this as follows:

ClassPool cp = ClassPool.getDefault();
CtClass cc = cp.get(C.class.getName());

cc.setName("newName");
cc.setSuperclass(cp.get(B.class.getName()));

B b = (B) cc.toClass().newInstance();

b.method();

The above code works fine when I call method(), but If I instantiate an anonymous inner class in C's method() like this:

public class C extends A {
    public int method() {
        try {
            return new Callable<Integer>() {

                @Override
                public Integer call() throws Exception {
                    return 5;
                }

            }.call();
        } catch (Exception e) {
            return 2;
        }
    }
}

when I call method() I get java.lang.NoSuchMethodError: C$1.<init>(LnewName;) error.

Answer 1

While I would love for someone to tell me differently I think this may not be possible with Javassist, I found the following line in section 4.7 of the Javassist tutorial:

"Inner classes or anonymous classes are not supported."

So I guess I should look into other runtime class generation libraries

Answer 2

Javassist doesn't support non-static inner classes.
See javadoc for method CtClass.makeNestedClass(String nestedClassName,boolean isStatic) .
Your problem can't be resolved unless you move to top-level your anon inner class.