Here are my tips:
1. Work out (not just read) Khalid Mughal. It is really great experiance working through his book.
2. Do not miss K&B once you are done with Khalid. Because, K&B will help you to prepart from exam point of view.
3. Easy sections on exams were: collection & maps,java.lang package,operators and assignments, threads.
4. garbage collection questions are tricky. They are NOT straighforward.
5. Exception handling will be tough. so work it out more.
6. Lot of questions on threads but if you remember few basic things
you should be scoring 100% on that. They key is "nothing is deterministic when it comes to threads'. so look the question properly and apply semantics of start(),run(),wait(),notify(),sleep(),join(),yield() methods. deprecated methods are not on the exam. so just read these methods.
7. operators and assignments are good. make sure that you dont feel lazy working through such questions (sometimes loop questions are simply lengthy so we tend to miss just because of impatience. work it on paper. you will get it.)
8. in your last week, go through all posts at javaranch.com. most of the questions are similar to what people ask here.
9. dont miss shift operators. they are damn easy. just understand 2'complement math to work out ~,<<,>>>,>> operators. make sure you calculate shift value on paper.
10.Assertions are new to 1.4 but they are really easy. just remember key things about it. like it can be enabled at package level as well as class by class levels. it needs some value on expresion2. and expression1 must be boolean. ways of enabling/disabling assertions.
11.equivalent loop structure of foor loop. make sure u know what is equavivalent while loop for the given for loop & vice-versa.
12.don't go deep into collection &maps. just understand what is to be used on which situations.
regards
