Good luck with the exam Dolly!
If you're getting a good score on the mock exams then you're well prepared for the exam.
According to Sun there are 10 extra questions in the exam now, so you'll get 82 instead of 72 questions. You will get 40 minutes extra time for those questions. The extra questions will not count for your score on the exam.
Sun does this to test out new questions for the
SCJP exam. Note that they don't tell you which of the questions are the extra questions, so you'll have to pay attention to all 82 questions.