Here are two projects I saw on comp.lang.java.announce and thought interesting enough to explore them further:
Dependency Finder will take compiled Java classes and examine and report on dependencies. It can also take different versions of the same class and report on changes to its API. It comes with Ant tasks to allow these to be automated at compile or distribution or test time. Worth downloading and checking out.
The OpenEJB project looks interesting. It is an open source EJB container. According to them
As a container system, OpenEJB works like a big plug-in for middleware servers like Web servers, CORBA servers, and application servers. By plugging in OpenEJB these servers obtain instant EJB compliance for hosting Enterprise JavaBeans!
I don’t have an immediate use for this, but if I need something like this I’ll keep it in mind.
Since I started using Eclipse for my Java IDE I find something cool for it at least a few times a week. Last week I found an Eclipse plugin that does profiling of method calls whilst running your project in a captive Eclipse VM. Cool stuff, and it allowed me to speed up some code dramatically by improving the hot spots.