Hi Asha,
I highly recommend you to buy WhizLabs simulator.
I've really threasured each cent I paid for it.
WhizLabs contains 6 full mock exams plus 150 quiz questions. After write the diagnostic exam, which is tougher than real exam, WhizLabs' reports give you a large idea where you have to make efforts in order to archieve the
SCJP and win your weaknesses.
I also cannot forget about WhizLabs refund policy : If even after purchase WhizLabs simulator you still cannot pass the real exam, they are engaged to refund you all amount you spent.
"If someone asks you to do something you don't know how to, don't tell I don't know, tell I can learn instead." - Myself