The i18n.jar file in the J2RE contains three separate sets of classes:
- locale data supporting java.text and java.util functionality for all locales other than en_US,
- character converters required for the platforms that the J2RE runs on (Windows, Solaris, Linux),
- character converters not required for these platforms.

None of these are really internationalization (localization might be closer, but even that's not fully appropriate), and the name has caused considerable confusion. Also, the core runtime currently knows about this jar file and gives it special treatment. This is only needed for the platform character converters (to enable basic file access), but not for locale data and the non-platform character converters. Finally, the non-platform character converters are not needed by most users and should therefore not be included in J2RE-only downloads where size is a major concern (they may in fact be removed from the J2SDK entirely).

The file should be broken up and the pieces renamed to make their functionality more clear, e.g.:
- lib/ext/localedata.jar
- lib/charsets.jar
- lib/ext/charsets.jar