Develop XUL application and connection (JavaScript) with Java classes

Hello,
I want to develop XUL client application which will use some Java
classes I develop. I just want to call some methods in Java which will
return some results.
How can I do that?
Can I use JavaXPCOM to make connection between XUL (JavaScript) and
Java? Can I use LiveConnect from XULRunner and is it better to use
LiveConnect then JavaXPCOM?

Where can i find a demo about JavaXPCOM?

Thanks, Marko Dudic