What is the best way to deploy a Java desktop application to multiple platforms?

Question

I'm writing a Java application intended to run on the desktop, which will use Swing for its UI. I'm familiar with Java Web Start, but have heard that it can be cumbersome and buggy.

What tools are available to make it easier to deploy Java applications to multiple platforms? I'm particularly looking for freely available tools, or at least tools that are free for use with open source projects.

edit: I should clarify that this is for a peer-to-peer application that will predominantly run in the background, and should (optionally) be able to start automatically on Windows, Mac, and Linux.

edit2: I should further clarify that this app is intended to operate in countries where the government may censor our website. As such, its important that it can be distributed as a stand-alone file, rather than something that must be downloaded from a known website.

Answer 1

Java Web Start is currently the best technology for platform independent centrally controlled distribution of Java programs.

With the update of JWS in Java 6u10 things were improved quite a bit - previously especially caching was a problem.

We have found that by ensuring unique URL's to the jar files for each new release instead of reusing them, the cache problems almost went away.