is it possible to detect when the connection between application and database fails (for any reason, like network problem or max users exceeded) ?
I implemented the ConnectionValidator (as says on Chapter 9 Doc) but without success. There is some other configurations to do (or another path to follow instead ConnectionValidator) ?
The ConnectionValidator monitors the health of a connection on the client side. Remoting sends invocations from the client to the server and returns the results. It doesn't handle connections between the server and a database. I suggest you post the question on the AS forum: https://community.jboss.org/en/jbossas.