I just spent an hour playing with Groovy, and I have to say that it is very promising. I have not experimented a whole lot with the actual Groovy syntax, but based on what I have read as well as on my limited experiments, Groovy is a nice mixture of popular scripting languages such as Ruby or Python, but geared towards Java programmers....
Martin Fowler shares some thoughts on JUnit, mostly about why JUnit instantiates a new instance of the test class for each test case. As usual, he has some good points. The posting also contains some information on JUnit's TestSetup feature, which allows several test cases to share a single setup and teardown routine.
Prevayler 2.0, a prevalent persistence engine, was released a few days ago. This is the first time I have heard about this project or about this type of persistence engine, but it sounds very promising. Prevayler can be used in lieu of a (relational or object-oriented) database in many cases. It is based on simple mechanisms that are built into the Java language, in particular serialization....
I'm still evaluating Eclipse 3.0 to see if I could imagine switching from IntelliJ IDEA to Eclipse. Overall, I'm still pretty impressed with Eclipse, with the exception of a few shortcomings I mentioned before. Another important feature that Eclipse lacks out of the box is support for XML editing....
EclipseME is an Eclipse plugin for J2ME development. I have not installed it yet, but it sounds well worth checking out....