I am grateful that I was given the opportunity to pass this SJCP exam.
Thanks to Javaranch for providing very helpful materials. I did some of the mock exam 1.4, 2 Simulators' sample questions and Sun's sample questions. I also have the Java Certification book by Kathy and Bert (around 200 questions).
The sample questions in simulators and Certification book are a lot harder than the real exam. Passing score for SCJP is 59%. I scored 60% for each of them (bad indication) but scoring 90% in the exam. So, do not let practice questions results discourage you. I guess the questions are purposely made harder so you can score high.
Sun's 10 sample questions are the typical questions you will be asked on the real exam.
The book helps limiting the API you need memorize.