LEGO MINDSTORMS (http://www.LEGOMINDSTORMS.com) is a Robotics Invention System that consists of a number of LEGO parts , a microcomputer called the RCX, an infrared transmitter (connected to the serial port of an ordinary computer), and various sensors and motors. Using this system, one can build an almost infinite variety of LEGO robots that can be controlled by the RCX. This RCX computer can be sent "immediate" commands, or can have a (small) program downloaded and then run.
MINDSTORMS is a pretty cool system that can be driven at a number of levels. A primary audience for programming this system is children, and there is a visual programming environment to help in this. This visual environment only runs on Windows or Macintosh machines, which are connected to the RCX by their serial port and the infrared transmitter. Behind this environment is a Visual Basic set of procedures captured in an OCX, and behind that is the machine code of the RCX, which can be sent as byte codes on the serial port.
The RCX computer is completely incapable of running Jini. It is a 16-bit processor with a mere 32 K of RAM, and the default firmware will only allow 32 variables . It can only be driven by a service running on, say, an ordinary PC.