nothing stops you from performing a cold deploy, JBoss is able to reload the deployed .ear or .war file dynamically once you copied the file into deploy  directory, this will push the file to deploy reloader. as far as I know this applied to app app servers , you don't need to restart the whole server, its just restating the application  itself.

the last version of jboss  is JBoss-4.0.4
and it is not neccessary to restart your application  server to deploy  just deploy your war or ear into the deploy folder in jboss server  and it should work.

If you deployed your application  before and now you want to just redeploy it
because of a little change, just touch the WEB-INF/web.xml file (open
it and make a little change in it and then save  it!). then Jboss will redeploy
your application.