leJOS is a Java-based replacement firmware (OS) for LEGO Mindstorms programmable bricks, including RCX and NXT. It supports threads, exceptions, synchronization, floating point arithmetic, strings, and so on, but there is no garbage collection yet. It is also designed to be portable to other small devices.


leJOS NXJ is a full replacement firmware JVM that allows you to run Java programs on the LEGO Mindstorms NXT brick. leJOS NXJ works with Windows, Linux, and Mac OS X. Version 0.3 includes a flash file system with implementations of java.io.File, FileInputStream, and FileOutputStream, a menu system, Java streams over Bluetooth and USB, support for LCP (LEGO Communication Protocol) including file commands, a file explorer that runs on your PC, and much more.

URL: LeJOS, Java for Lego Mindstorms