As I've been studying for the Sun Certified Java Programmer exam and I've found that some topics and concepts just aren't sticking. I've begun keeping a study log of problem areas and I'm writing some code for every topic or concept I'm confused about. Hopefully some of these will be helpful to others who have difficulty mastering the exam content.
All of this code was created in generic text editors without an IDE. Some of the code is formatted strangely because that is the way the exam code is written and I wanted to internalize their madness. Any actual Java I wrote for a personal or professional project would show better naming standards, clearer blocks and follow the style guide of the project. Trust me, I hate the way those questions are written on the test as much as the next guy, if not more. :P