2.2.1. Using yum / RHN (Preferred Method)
Update your RHEL5 installation and install the JVM as described above.
Subscribe to the Red Hat Application Stack child channel:
e.g: rhel-x86_64-5-appstk-2 or rhel-i386-5-appstk-2
Install JBoss Application Server:
For the Application Server (which includes an embedded Tomcat), run:
yum install jbossas
Refer also to Chapter 4, Using JBoss Application Server below.