I have cleared the Sun SCJP 6.0 exam yesterday with 80%. This is my second attempt. In my first attempt, exam pattern was completely different with 72 questions, pass % is 65% . I lost that exam by just one mark.
New pattern, questions are small in size but tricky. I encountered more questions on Interface, Inheritance and Static. I saw almost all topics are covered which are from Navigation to Generics to Threads to Development to Assignments to Operations.
Previous format, Multi-threading questions were horrible, means were very big questions and understanding and selecting answer was taken at least 5 mins.
Useful books are SCJP 6.0 from K&B is very good. This is the best book. Don't forget read comments. And read each and every line, attempt all questions in back of each chapter.
Another book is SCJP6.0 by Khalid.
To understand the Generics, study the Sun documentation, it will really gives the full idea of generics.