A servlet container and JavaServerPage? implemention (ReferenceImplementation in fact). Very big in WebServices and a key part of JBOSS?.
Recently ApacheTomcat? 5 was released. Anyone migrating to 5 will probably need to rewrite their web.xml file, since 5 validates it against the applicable DTD and is much more strict about what syntax it accepts, especially with respect to wildcards.
No other page links to ApacheTomcat yet.