Full round replay — overloading and overriding

Pass: No — a same-signature static hides the parent's, and hiding is resolved from the reference type at compile time. invokestatic never consults an object.

Fail: 'Yes' — or 'no' with no idea what happens instead.

Pass: No. A subclass field with the same name shadows the parent's; both exist in the object and which you read depends on the declared type of the expression. Same rule as static methods.

Fail: 'Yes, if they're protected.'

Pass: describe(Object). Overload resolution is a compile-time decision from the declared type; the runtime type never enters into it. A cast changes what the compiler sees and so changes the answer.

Fail: 'describe(String), because it's really a String.'

Pass: describe(String) — the most specific applicable overload. If two were equally specific, say String and Integer, it would not compile at all; you disambiguate by casting the null.

Fail: 'NullPointerException' or 'describe(Object)'.

Pass: Parameters: nothing. Return: may narrow to a subtype since Java 5. Access: may widen, never narrow. Checked exceptions: may narrow or drop, never broaden. And the parent method must not be private, static or final.

Fail: Gets return covariance or the exception direction backwards.

Pass: Resolution runs widening, then boxing, then varargs, stopping at the first phase with a match. The order exists so that pre-Java-5 code kept binding to exactly the methods it always did when boxing and varargs were added.

Fail: 'It's faster' or 'declaration order'.

Pass: equals(MyType) is an overload, not an override, so collections calling equals(Object) get Object's identity version. @Override would have made it a compile error.

Fail: Blames hashCode alone, or the collection.