Mr. Brogen, in Chapter 3, test question 10 -- I have a real problem with your answer on that one. You've implicitly cast a Long object to an Object. Everything I've read says that when you do this, you only have access to the methods in the item on the left, the "larger domain". The Object domain implements "equals" as a simple "=="; it checks to see if two objects are "the same", NOT if they have the same contents. Since you didn't state that there was an overridden implementation of 'equals' in the Long object, I have to assume it uses the one in Object. Therefore the statement at line 5 ( if (A.equals(L)) would yield false and your answer is wrong. Please let me know your thinking on this. I hope that the answer does not indicate that I'm supposed to know the implementation of every class in the API by heart, including Long.