I passed the OCP/JP exam today. The last couple weeks of studying were rough, because I have a ton going on. I got a pass... not a high pass, but a pass.... and put myself one step closer to getting my degree at WGU.
Here's my tips:
1. Two must-haves are the K&B SCJP book and Enthuware. I found the questions on the cd with the book were WAY too hard, and not a good gauge for me of how well I was doing. The enthuware questions (and there are hundreds) looked a lot like what the exam questions looked like, and the score I got was VERY SIMILAR. I went through each chapter of K&B and then finished off with using "practice mode" with the questions for that domain. I got examcram from my school.... I was not crazy about it.
2. The third must have is the SCJP forum here. Ask questions. Look at what other folks are asking. Compile and run code from practice tests and ask questions about it there. Java geniuses hang out here on the Ranch. Ask questions!
2. Don't try to know everything. The exam isn't THAT hard. Know enough that you can get through the rest. Know the stuff that's easy to you REALLY WELL.... for me it was declarations and scoping.... then it gives you some room to fudge the stuff you don't know well.
3. When the questions ask "how can you get this to compile" -- well, don't think about it too long. It doesn't need to make sense, you don't need to use the variables in the method calls, just make it compile. I found myself spending LOTS of time scouring answers for something that made sense and just settled on, "well, this doesn't do anything useful, but it will compile.... and the others won't."
4. I should have studied collections more, and I think I spent too much time on generics and threads. It seemed every API I was tested on had to do with collections. Know them.
5. I got 12 drag and drop questions. There were only 2 or 3 that were really tricky. I did find it hard to get the answers to "stick" to where I wanted them.
6. Understanding command line / classpath / jar questions -- that's a gimmie. You know it will be on the exam and there's a limited amount of stuff they can ask.
When you do things right, people won't be sure you've done anything at all.