SupportMQExtensions property
The JMS 2.0 specification introduces changes to the way certain behaviors work. IBM® MQ 8.0 includes the property com.ibm.mq.jms.SupportMQExtensions, which can be set to TRUE, to revert these changed behaviors back to previous implementations.
Three areas of functionality are reverted by setting SupportMQExtensions to
True:
- Message priority
- Messages can be assigned a priority, 0 - 9. Before JMS 2.0, messages could also use the value -1, indicating that a queue's default priority is used. JMS 2.0 does not allow a message priority of -1 to be set. Turning on SupportMQExtensions allows the value of -1 to be used.
- Client id
- The JMS 2.0 specification requires that non-null client ids are checked for uniqueness when they make a connection. Turning on SupportMQExtensions, means that this requirement is disregarded, and that a client id can be reused.
- NoLocal
- The JMS 2.0 specification requires that when this constant is turned on, a consumer cannot receive messages that are published by the same client id. Before JMS 2.0, this attribute was set on a subscriber to prevent it receiving messages that are published by its own connection. Turning on SupportMQExtensions reverts this behavior to its previous implementation.
This property can be set either as a standard JVM System property on the java command or contained within the IBM MQ classes for JMS configuration file.