leJOS is a tiny (~ 16 Kb) Open Source Java-based operating system for the LEGO MINDSTORMS™ RCX,
i.e. Hitachi H8300.
It supports the RCX versions 1.0, 1.5 and 2.0 and works with the serial IR Tower as well as with the USB one.
The first release was developed by Jose Solarzano and eventually forked out of the
The software consists mainly of three parts:
a Virtual machine for the execution of Java bytecode
an API for RCX programming on top of this VM
additional software tools
Object oriented language
Floating point operations
For more information you might want to visit the leJOS project homepage at
The leJOS Tutorial