Water: a fast, secure, dynamic OO language and database. Water is an all-purpose language (and meta-language) that runs Web applications in the browser or server-side. Water is compatible with .NET, Java, and C on Windows, Linux and Mac OS X system.
Javum, the Java Virtual Unix Machine, is an ambitious project which aims to provide a full virtualized Unix environment including C compiler (GCC), Unix-like API, shell, and command line tools, inside of a JVM. Details @ http://javum.wiki.sourceforge.net
jRate is a real-time Java compiler and runtime system (based on GNU GCJ) with support for much of the Real-Time Specification for Java (RTSJ), including threading constructs with real-time constraints, asynchronous event handling, and memory regions.