RS232 Serial Communications In Java
How to use Java (javax.comm) for rs232 serial communications with Eclipse on WinXP
Download the package from: http://java.sun.com/products/javacomm/downloads/index.html
The zip contains a folder named commapi. Put this folder in eclipseplugins. In your project properties > add external jars, add comm.jar from eclipsepluginscommapi. The folder also contains a dll, you'll need to point to in the RUN setup. You can put the dll anywhere you like.
The important part is that [comm.jar] and [javax.comm.properties] are both in [eclipsepluginscommapi]. If they are anywhere else it will not work, and you will get the following errors: "Cannot find any ports", "No ports available", "No available ports".