A locale is a user community that shares a common set of linguistic, cultural, and territorial expectations and conventions. These conventions include, but are not limited to, how the local language is written, how dates, times, numbers and currency are formatted, and how strings are sorted. Just because an application has been internationalized does not mean that the application runs appropriately in any locale; the application must be supplied with appropriately localized resources before it can support that locale.

The process of customizing an application for a specific locale is called localization. Localization includes everything from translating messages to creating appropriate resource bundles containing relevant local data for use in a given locale. Users of internationalized software are involved in the process as well, when they select the local conventions they prefer from the set of conventions available in their environment.

The Internationalization Module localization classes support the writing of programs that can easily be localized. They provide the ability to name particular locales, and to store and access locale-dependent resources. The Internationalization Module contains these localization classes: