[xmedeko]

What you need is HA. Try to digg JBoss resources, you will find some documents about it. You also do not need JBoss way to HA, you can make it in OS level. E.g. Linux iptables stuff.

You can also do exploded deployment. Then you update just certain files. If you update just JSP pages, you even do not need to redeploy the app. When you update some libs or classes, then you just touch the WEB-INF/web.xml.

Anyway, HA is more robust solution.