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 The project has been superseded and replaced with TotalCross.
joeq is a Java 2 (JDK 1.3 and 1.4) compatible virtual machine. It is unique in that it is entirely implemented in Java, leading to greater reliability, portability, maintainability, and efficiency. It is also language-independent, so code from any supported language can be seamlessly compiled, linked, and executed dynamically.
OzVM (Virtual Machine Project) is a simple, lightweight, secure virtual machine. The current target application of OzVM is OzStream, which allows platform independent self-decoding of data. The vision of OzStream is to make any and all compressed media self-extracting. OzStream abstracts compressed media from client applications, providing new freedom for users, developers, and compression techniques.