The ATLAS (Automatically Tuned Linear Algebra Software) project is an ongoing research effort focusing on applying empirical techniques in order to provide portable performance. It provides C and Fortran77 interfaces to a portably efficient BLAS implementation, as well as a few routines from LAPACK.
SuperWaba is a VM for PDAs. Because of the way it was written, you can use Java to develop programs for it. It supports exceptions, threads, many user interface controls, double and long 64-bit types, grayscale, color, 3D controls, and JNI and Java libraries, among other features. The project has been superseded and replaced with TotalCross.
MiniPauker is a flash card based learning application for mobile devices and handhelds. It is based on the leitner cardfile system and is compatible with Pauker (http://pauker.sf.net, the desktop version of this software). MiniPauker uses a combination of ultra-shortterm, shortterm, and longterm memory. You can use it to learn all the things you never want to forget any more, like vocabulary, capitals, and important dates.
ElegantJBeans Developer Collection is a large collection of ready-to-use 100% Java Beans. The collection has beans for every developer need, whether it's related to UI, data binding, validation, data access, communication, reporting, printing, data analysis, or data monitoring. These beans provide tested and proven code.