The Java EE 5 Tutorial

Setting Message Priority Levels

You can use message priority levels to instruct the JMS provider to deliver urgent messages first. You can set the priority level in either of two ways.

The ten levels of priority range from 0 (lowest) to 9 (highest). If you do not specify a priority level, the default level is 4. A JMS provider tries to deliver higher-priority messages before lower-priority ones but does not have to deliver messages in exact order of priority.