JMS 2 made the JMSXDeliveryCount property required. However, dead letter queues remain non-standard although they are widely implemented and used. As a result, JMS application portability is needlessly limited and the feature is harder to use (often requiring digging around vendor documentation).
This proposal is to standardize the concept of dead letter queues and make them available at a standard location - e.g. java:comp/deadLetterQueue.