Enthuware

If passed a null it can also throw a NullPointerException, right? E.g.:

TestClass tc2 = null;
System.out.println(tc2.equals(null)); //does not return false, but throws NPE

(I picked answer "none of the above" instead of answer "must return false" because of this).

No, as per the requirements of the equals method, you pass a null, it should return false and not throw NPE. If a class throws NPE, then it is not an appropriate implementation of equals method.

HTH,
Paul.