I would suggest reading Effective Java by Josh Bloch, it has some great tips on how to write code and design APIs as well as nicely structured sample code. I'm

I would suggest reading Effective Java by Josh Bloch, it has some great tips on how to write code and design APIs as well as nicely structured sample code. I'm a much better developer (not just in Java) for it. Also browse some of the core Java source code to see really elegant implementations by him.