Why not Factor for the Java Virtual Machine or .NET?
Originally, Factor was written in Java, and there was a compiler to JVM bytecode. But, to improve speed and the foreign function interface, Factor was rewritten in C and Factor. JFactor was abandoned in favor of CFactor. At this point, basicaly no Factor code would work in the old JFactor unmodified, as JFactor is missing several key features like generic words and syntax extension. Factor is currently natively compiled, not bytecode compiled. Removing the dependency on the JVM makes portability and distribution easier.
