I think inner classes can extend any other classes. But there is no must and should that they have to extend some class.
Joined: Dec 10, 2001
But there is no must ... that they have to extend some class. Except, as Jim pointed out, the Object class. The Object class is always at the top of any class heirarchy. If you don't explicitly extend some class, then the compiler determines that you must want to extend the Object class directly.