I have a Web application written in Java that is targeting several countries, all of which speak different languages (and more often than not, several languages -- that's Europe for you).

We have a bunch of .properties files that hold the localized strings, and our current procedure is to e-mail the language-specific files to our partners for updating before doing major updates.

However, this process is rather error-prone, as sometimes people forget to translate new strings and sometimes new strings don't get added to every language file, thus small mistakes get through very easily.

Does anyone know of any existing software that could help us clear this mess?

At a bare minimum, I'm thinking of something that would allow you to load a master file (for example, in English), a localized file and then would highlight the keys that were added to or removed from the master file.