I cleared the exam today and happy with the score, though I thought the test deserved to score 100% - it was easy, but I could not say that if not for Javaranch (this is heaven for Java aspirants - no doubts), K&B and Khalid book (though I feel K&B is definitely all you need for the exam) and the active ranchers who respond to questions - that helps a lot. Thanks a lot. I Got 1 wrong each in Threads, GC and Assertions/Exceptions.
I am not Java expert, infact before a month I knew very little basics. SO I will give my input from that perspective and may not help the Java professional. The exam is not tough provided you do a lot of mocks - that is the bottom line. K&B book is great and that is all you need but your score will not depend on how well you know from the book but simply from how many mocks you can solve (not necessarily correctly but from how many you can learn from).
What I think are a few very important things I did:
1. Read all the inputs from all the people who score more than 90% in the last year and half (I wanted to score more than 90% so I didn;t read inputs from people who scores less than that) and formed my strategy based on that.
2. Someone had mentioned that the compiler is the best teacher, and I totally agree - infact I tried almost all the code I came across using Eclipse (which is great too). Best way to understand.
3. As I read and gave mocks, I formed my own notes of all the reasons why my answers were wrong and I got a lot of answers wrong in the mocks - scoring mostly between 50 to 75% most of the times (few Dan's tests even less than 50% the first time)
Hope this helps somebody as I was helped by the others. Finally here is how I prepared
1. K&B book + all self tests in it + Rules roundup
2. Khalid book + Dan's study guide 2 for chapter wise questions
3. Many of the mocks freely available
4. Few of the JQPlus and Whizlabs Mocks too.
5. K&B book again and Dan's comprehensive mocks
6. 2 of Marcus's and all 3 K&B Exams.
and then gave the test. But easily more than 2100 Questions in total.