SCJP - 3 -Which is true? (Choose all that apply.)

3. Which is true? (Choose all that apply.)

A. "X extends Y" is correct if and only if X is a class and Y is an interface.
B. "X extends Y" is correct if and only if X is an interface and Y is a class.
C. "X extends Y" is correct if X and Y are either both classes or both interfaces.
D. "X extends Y" is correct for all combinations of X and Y being classes and/or interfaces.

Answer:

C is correct.

A is incorrect because classes implement interfaces, they don't extend them.
B is incorrect because interfaces only "inherit from" other interfaces.
D is incorrect based on the preceding rules. (Objective 1.2)