Create a custom dock/application icon for .jar files built in eclipse

I've spent the better part of the afternoon trying to figure out how to apply a custom icon to jar file that I created in eclipse. I am presently using eclipse v3.5 on Mac OS X 10.6.2 and have yet to find a way to change the java coffee cup logo in the document icon for my jar files created in eclipse. Is there some way I can call a specific Apple class in Eclipse to change the dock/application icon of my .jar file?

I found this link that uses a class that seems to be specific to XCode to change the icon of the .jar file.

What I mean by change the icon of the jar file, I mean change the icon used in the dock, and also the icon used when the "command+tab" switcher pops up. Presently, I have the black console icon with the text "exec" in the upperleft.

If anyone has any good links on this topic or even better knows the code I need insert into my program I would be highly greatful.

cheers
-ipatch