The Jboss JCA Pool just uses the settings from the connection-url and it is the oracle RAC which does take control of the loadbalancing/failover .
However if you want the failover to be taken care by the Jboss JCA then you will have to configure ha datasource , this does not take care of loadbalancing yet .
I was not able to get any one interested in this so have kept this on hold
Does JBoss somehow integrates with Oracle ONS (Oracle Notification Services)?
I am not sure what do you mean by this , check if this can be configured through the datasource descriptor file .
In order to benefit from Oracle RAC features like fault tolerance and load balancing all you have to do is configuring the connection url with the list of Oracle hosts which belongs to the cluster.
In this example we are configuring our datasource to connect to a RAC made up of host1 and host2: