toUpperCase()
or toLowerCase()
calls on String
objects that do not specify a
java.util.Locale
. In these cases the default system locale 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
in a Turkish locale, will return incorrect results. Alternatively, when dealing with strings that should be treated as locale-independent,
like HTML tags, this can lead to errors.