Small Devices

Waba "is a programming platform for small devices. Waba defines a language, a virtual machine, a class file format and a set of foundation classes. [...] The syntax of the Waba programming language is a strict subset of the syntax of the Java language."

SuperWaba is a commercial derivative/fork of Waba.

Ewe is another derivative of Waba.

There also exist micro/embedded/personal editions of Java, as well as light-weight JVM implementations, which may or may not support standard Java.