interface Message {
    public void methodA();
    public void methodB();
}

interface Request extends Message {
    public void methodC();
}

abstract class MessageBase {
    @Override
    public void methodA() {}
}

abstract class RequestBase extends MessageBase implements Request {
    @Override
    public void methodB() {}
    @Override
    public void MethodC() {}
}

class RequestImpl extends RequestBase {}