private void privateMethod() {}

        OldSuperInternal returnTypeOverridenMethod() { return null }
    }

    static class OldBase extends OldSuperInternal {
        void anotherPublicMethod() {}

        OldBase returnTypeOverridenMethod() { return null }
    }

    static class OldSub extends OldBase {
        OldSub returnTypeOverridenMethod() { return null }
    }