Reread the file. jboss is not preventing you from picking up runtime changes.
Thanks for your reply and I hope you will forgive my ignorance on the inner workings of JBOSS. But how do I reread the file once JBOSS is going? Is there some command I can send to it while it's running to do that?
I don't think that the SystemPropertiesService scans more than once (when the app server starts). I think what Scott is trying to say is that you can write your own code to rescan these files on an interval to see if they have been updated.
You might consider trying to extend the service class that is used to load the system properties:
The MBean definition is in the deploy directory under properties-service.xml. You could extend it to add a rescan interval and some code that compares the timestamps of the properties files in the URL list.