Using JINI with Linux

Introduction

JINI is a new technology implemented in pure Java ontop of the JDK 1.2. It defines a framework for the interaction of services and service-consumers. Design goals were simplicity, reliability and scalability by low to none administration overhead (e.g. no drivers to install). You can find information about JINI at various places like http://developer.java.sun.com/developer/products/jini or http://www.jini.org.

This page is no introduction to JINI. It just wants to give some hints for using JINI together with Linux and provides some sample code. It wont be of any help if you don't have an understanding what JINI is about and how it works.

Linux and JINI

Since JDK 1.2 is available for Linux, there is no problem running JINI on the Linux operating system. There is one thing to watch out for: a core feature of JINI uses IP-multicasting. If you don't know what this is, check out the appropriate HOWTO. Make sure that the kernel you are using is multicasting enabled. You also have to put the interface in multicasting mode and set a correct route:

# ifconfig lo multicast
# route add -net 224.0.0.0 netmask 240.0.0.0 dev lo

Scripts and Sample Code

You can download two tarballs. One with scripts useful in setting up the JINI environment (e.g. a script starting the lookup service, a webserver and the RMI activation deaemon) and one with a sample application. This application is a service making all entries in the local /etc/printcap available for clients in the JINI-community. A simple client is also supplied for testing purposes.