interface J<A, B> extends T<A, B> { @Override <C> int foofoofoo(A a, B b, C c); } abstract class J1<X, Y> implements J<U<X>, U<Y>> { @Override public <C> int foofoofoo(U<X> xu, U<Y> yu, C c) { throw new UnsupportedOperationException(); } } abstract class J2<X> extends J1<X, String> { @Override public <C> int foofoofoo(U<X> xu, U<String> stringU, C c) { throw new UnsupportedOperationException(); } } class J3 extends J2<Object> { @Override public <D> int foofoofoo(U<Object> objectU, U<String> stringU, D c) { throw new UnsupportedOperationException(); } }