This might not related to JBoss, the Oracle documents say:
ORA-12519: TNS:no appropriate service handler found
Cause: The listener could not find any available service handlers that are appropriate for the client connection.
Action: Run "lsnrctl services" to ensure that the instance(s) have registered with the listener, and are accepting connections.
Check your parameter, ask an admin
or try a jdbc client like Squirrel to check the database first.