Pragya,
About the materials that I used...
RHE was a goos way to start. I also referred to Core Java Vol II by Cay Horstmann and Gary Cornell. It's got good explanations for Threads and Collection, List, Set, etc. All my other study materials involved dwelling on this site for hours together and going thru' all the discussions, past and present. I got to know a lot of intricate points this way which really helped during the exam.
About tips...
Try writing as much code as possible to try out different possibilities and learn from the results. Take all the mock exams mentioned in Maha Anna's page
here. Draw up a table of the different types of streams and readers with their use, constructors and read methods. This really helped me in understanding the different streams and readers. Get to know the API specs for important classes well.
One final tip..never lose heart. Keep trying!
Good luck for your exam.
Srikrish.

[This message has been edited by srikrish (edited September 18, 2000).]
[This message has been edited by srikrish (edited September 18, 2000).]