From the ffmpeg-list:
>>> Java is rumored to be platform-independent.
>> Highly overhyped rumor, it actually runs on all platforms... that have a JVM.
> Right, both of them. :) Funny essay on the matter:
> http://web.ivy.net/~carton/academia/java_languageoftomorrow.html

And congratulations to the marketing guys of sun who managed to promote their product for years with something that just isn't true.