JUnit

JUnit is a pretty straightforward framework, so on one hand, I have provided you more than enough information to do unit testing. On the other hand, several other tools and utilities available on the junit.org website might be worth checking, such as various mock objects, JSystem, JUnit PDF Report, and many others.

I would also encourage you to explore the Test-Driven Development (TDD) approach, which advocates writing tests first. This method of working takes some getting used to, but after you do, you will probably want to continue working only in this fashion. Again, give this approach some time because initially you might feel that you are spending more time writing tests; but if you factor in the amount of time you spend unit testing your code and fixing defects reported by your testers or users, you will begin to see why this approach can actually save you time. Also, this technique works best if you write small chunks of code (for example, smaller methods and classes versus big and complex ones).