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 The project has been superseded and replaced with TotalCross.
jSyncManager is a Java-based data synchronization toolkit for PalmOS handhelds. It consists of a developers API, including a fully Palm-compatible synchronization protocol stack, and a set of end-user applications. It is ideal for use by any individual or organization that needs fast, stable, and easily extendable PalmOS handheld data synchronization that can run on a variety of platforms. It also supports plug-ins, which can be used to add synchronization support to applications, and includes a variety of import and export modes, including XML and CSV.