The EmailAlertListener works and is specific to the web-console. I think the name is a bit missleading because it doesn't actually 'listen' for notifications, it waits for notifications to be push to it, which is not correct, IMO and it expects a particular notification class.
On the other hand, the MemoryMonitor creates its own thread, monitors the memory and produces 'alarms'. It also produces 'seizure' alarms, when the memory gets back to normal.
The Notification listener is a generic JMX notification listener that can be used to subscribe to any mbean/notification combination in the system and output the notifications to the console. (To configure the SubscriptionList look here http://www.jboss.org/wiki/Wiki.jsp?page=SubscriptionList)
The last 2 can work together, but the EmailAlertListener is of a different design, so I don't think it can cooperate with them without writing some code. I'll try to fix this in one of the next version.
So is there any way to accomplish this (sending email when memory gets low) without writing code?