This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
We hear the following kind of statement from our SCJP trainees many times, "...I didn't think they would ask about it because it wasn't mentioned in the objectives, but I glad I studied it anyway." This could be because of the reason that Bert mentioned or because of something else.
Another issue is that every topic does not necessarily have a clearly defined area. It may unintentionally touch upon some other topic that has not been explicitly mentioned in the objectives.
Regardless, we believe that there is no harm in reading/learning a few extra things that seemingly are beyond official exam objectives. Because no matter whose fault it is, it is the candidate who loses the marks