When a WebLogic Server distributed destination member fails, the JMS resource adapter for the inbound MDB container closes any existing connections and sessions and opens new ones to an available cluster member.
If the failed cluster member is restored, or a new member is added, the JMS resource adapter rebalances the workload so that the messages are evenly distributed to all distributed destination members. The JMS resource adapter listens to the destination member UP and DOWN events to achieve the rebalance. To obtain this behavior, you must disable server affinity and enable load balancing. For information, see Load Balancing for JMS in Administering Clusters for Oracle WebLogic Server.
For failures that cannot be recovered from quickly, the adapter logs the failure and retries periodically.