Reports any call of toUpperCase() or toLowerCase() on String objects which do not specify a java.util.Locale. In these cases the default locale of the system is used, which can cause problems in an internationalized environment.

For example the code "i".toUpperCase().equals("I") returns false in the Turkish and Azerbaijani locales, where the dotted and dotless 'i' are separate letters. Calling toUpperCase() on an English string containing an 'i', when running on a Turkish system, will return incorrect results. Alternatively when dealing with strings that should be treated locale independently, like HTML tags, this can lead to errors.