Hi,
I mainly studied the study guide by Kathy Sierra and Bert Bates. The book is very helpful and the self exams at the end of each chapter are very close to the real exam. But I think they are a little bit tougher than the real exam. I have done most of the exercises mentioned in the book. Also there is another book called "OCP
Java SE 6 Programmer Practice Exams" that contained 4 full tests. The tests were really tough and if you can get 70% in them, then you will surely score good marks in the real exam. The book also contained a lot of small coding exercises which were surprisingly too helpful in memorizing things. So I did most of the exercises not in eclipse , but directly in notepad as they told in the book.
So overall it was a regular and sincere preparation for the past 5 months which helped me to achieve the goal. All the best to you.
Thanks and Regards,
Renju