for SCJP 1.5, you can atleast take the three mock exams : The two master exams and Whizlib diagnostic tests. Also try various mock exams from the list . Try markus green exams. (Skip the questions related to swing, Byte related IO and bit operations)
I found the exam somewhat easier than the master exams. But be prepared to face some tough questions.
If you have highlighted important topics in K&B then it will be easier for you to read them now. Otherwise, you can still read-thorugh the book again and highlight important points to refer later.
There will be questions from almost all exam objectives. As far as number of questions is concerned, I am not aware about what weightage is given to what topic. But the questions that I got had a mix of all topics. I don't remember any topic being left out.
You can go through some tips given
here. Also do check the advices given by Other ranchers in the Results Forum. I read them and found them quite useful.
[ August 23, 2006: Message edited by: Neelesh Bodas ]