What kind of books should i exactly prepare to get certification in sun.... is it necessary to undergo training before attending the exam... is there any free exam simulator available over net for free usage...

Man, seriously. the exam is a piece of cake. I think they are just trying to make some money now. Initially when exams came out, it was hard and only few people obtain certification. I just passed the sun certified java programmer during my winter break in university. It just took me 5 days or so. Its just multiple questions and drag/drop. no programming, which i found it bad. I think there is free assessment exam on Sun website, and try to google some SCJP "Sun Certified JAVA programmer" books. Try to review comments from amazon, which might help. I think sun also sells some tests online.

Overall: it was much easier than any of my classes in university..haha
Hope that helps.