One of the hosts in the JMS Hosts list is designated the default JMS host, named Default_JMS_host. The Application Server instance starts the default JMS host when the Java Message Service type is configured as LOCAL.
If you have created a multi-broker cluster in the Sun Java System Message Queue software, delete the default JMS host, then add the Message Queue cluster’s brokers as JMS hosts. In this case, the default JMS host becomes the first one in the JMS Hosts list.
When the Application Server uses a Message Queue cluster, it executes Message Queue specific commands on the default JMS host. For example, when a physical destination is created for a Message Queue cluster of three brokers, the command to create the physical destination is executed on the default JMS host, but the physical destination is used by all three brokers in the cluster.