UBD situation.

The problem was due to an error in the conf/web.xml file when parsed against later versions of the servlet specification as specified by the version attribute of the <web-app> element. There were two instances of the <session-config> element, which generates an error in Tomcat's server log. When the version was 2.4, parsing is more forgiving.

With the removal of the duplicate <session-config> element, the MIME type lookup functions as expected when the version attribute is set to 3.1 or 4.0.