In Java 8, the mechanism to select a locale service provider changed.
By overriding the isSupportedLocale method,
LocaleServiceProvider implementations can now determine whether the given
Locale is supported.
By default, the isSupportedLocale method returns true if the given locale equals any of the
available locales that are returned by the getAvailableLocales method, ignoring
extensions in both the given locale and the available locales.
This rule flags classes that extend the following Java 7 LocaleServiceProvider classes:
Evaluate your locale service provider to determine whether the default implementation
of the isSupportedLocal method is sufficient or whether you need to override the method to
provide locale support as intended by your provider.
For more details about the changes in Java 8 and the isSupportedLocale method, see the
java.util.spi.LocaleServiceProvider class documentation.