Those are the extensions for JSP files and tag files in xml syntax. As you may know there are two alternative syntaxes for JSP: the traditional one (using <% %> for scriptlets, for instances) and the XML variant (using <jsp:scriptlet>
</jsp:scriplet> . ). There are several ways to configure your web container to treat files as documents (XML) instead of traditional syntax files. One of those (for JSP 2.0 and higher) is to give the extension .jspx and .tagx for JSP files and tag files respectively. See also
this thread. [ December 04, 2007: Message edited by: Jan van Mansum ]