Both Tomcat and Oracle XML DB use port 8080 by default. Before installing JBoss I first changed the default port for XML DB as suggested here.
call dbms_xdb.cfg_update(updateXML( dbms_xdb.cfg_get() , '/xdbconfig/sysconfig/protocolconfig/httpconfig/http-port/text()' , 8081)) /
I restarted the Oracle database and verified port 8081 was in use and not 8080.