[FILEUPLOAD-229] If an actual lower/upper case is required, then should use a fixed locale (unless the code is intended to use the default locale, which is quite unusual for Commons). A suitable locale is Locale.ENGLISH as that behaves well with ASCII and ISO-8859-1.
commons/proper/fileupload/trunk/src/main/java/org/apache/commons/fileupload/ParameterParser.java