SuperWaba is a Java VM for Palm and Pocket PC handhelds that provides an alternative to J2ME.
It has support for exceptions, threads, lots of user interface controls, and double and long 64-bit types. It has grayscale and color support, a beautiful set of 3D controls in Palm OS, and support for JNI and Java libraries. It is also is fast and small, lets you use all device's memory if needed, and supports Symbol scanners, sockets, and serial/IR.