In JBoss 3.2.3 (Tomcat 4.x) it was possible to create a Virtual Host and set of Aliases in the jboss-service.xml and then map the webapps to the aliases through the app deployment descriptors. In tomcat 5 this works for some apps that have been deployed. The rest throw a 400 error saying no virtual host has been configured. The same apps mapped directly to the actual vhost (not alias) do not throw this error. The previous behavior can be useful for builds which target multiple environments (stage/test/prod/etc). Moreover it should be preserverd for backward compatibility.