The XmlChars and XmlNames classes are useful when working with XML symbols, which must obey certain rules. For example, when creating XML text, it is important to know that the element, attribute, entity, and notation names being used are really XML Names.
The MessageCatalog class will look up and format messages in a specified locale. It supports applications which provide such messages in locales chosen by their clients, and which may differ from the various defaults supported by different packages.