I remember a discussion ( somewhere, somewhen long ago) about a probable
bug with ResourceBundles, that they stay in memory (because of caching)
and that they should be dropped from cache somehow.
Maybe its a good idea to use one of the WeakReference-things to drop it
when no longer needed.
Another idea: invent a System.property to control cache-behaviour.
With a useful default, users can tune as they like:
cache, no cache, cache forever, cache with expiration...