No, deploy directory is scanned during start and periodical if hd-scanner is active
Does JBoss support a lazy deployment feature? So, instead of deploying all the ear's in the deploy directory, it simply deploys the ear when a request comes for it?
Well, the AS needs to know what's inside of the deployment.
For ears that's a lot of things that could trigger its usage, hence quite complex to support this.
We do have some support though, more on a classloading level.
See jboss-deployment.xml in http://community.jboss.org/wiki/JBoss5custommetadatafiles.
Otoh, for wars the trigger thing is easy -- first http request.
Afaik, we already do this for our admin console -- try browsing around a bit, imho there should be some wiki on this topic.
MC's state machine has On_Demand notion, which is currently supported for services.
But since there is a single abstract component model, this could be probably extended for deployments as well.