As I mentioned before, the mock exams from Sun are great for preparing you to answer the multiple choice questions on the real exam. But they are not good for preparing you for the drag and drop questions because there are no D&D questions on the Sun mocks. Even so, I still recommend the Sun mock exams.
Do not be discouraged about not passing the exam the first time. To be honest, the Sun Java 5.0 exam was probably the hardest exam I've ever taken. You have some experience in taking the exam now, and I'm sure you will only do better the next time.