Exercise

QUESTION
--------
interface X {
	void x ();
}
interface Y extends X {
	W y ();
}
interface W {
	void n ();
}

class A {
	void k () { }
}

class B extends A implements Y {
	void l () { }

	...  // You can infer which methods must also be implemented
	     // here based on the fact that B implements Y
}

final B b = new B();
b.XXXX();     // What method names can replace XXXX so that the code compiles?

ANSWER
------
b.y(), b.l(), b.k(), and b.x() are all valid.

b.n() is invalid. However, b.y.n() is valid.