Just as a tidbit:
Even (((A)null)instanceof A) will return false.
(If typecasting null seems surprising, sometimes you have to do it, for example in situations like this:
public class Test
{
public static void test(A a)
{
System.out.println("a instanceof A: " + (a instanceof A));
}
public static void test(B b) {
// Overloaded version. Would cause reference ambiguity (compile error)
// if Test.test(null) was called without casting.
// So you need to call Test.test((A)null) or Test.test((B)null).
}
}
So Test.test((A)null) will print a instanceof A: false.)
P.S.: If you are hiring, please don't use this as a job interview question. :D