It seems to be a customised version of tomcat though.
I moved a web app from tomcat to Jboss and I am having a few problems setting server level parameters.
e.g. in Tomcat you can set up context-params at the server level (conf/context.xml) or overwrite what is in conf/Catalina/localhost/<context>/xml. Jboss won't even parse files with these entries in. It seems to have a different xml schema for these files.