Contrary to the documentation sorted queues put messages without a sorting key at the head of the queue

The documentation for sorted queues [1] currently states:

Messages sent to a sorted queue without the specified JMS message property will be inserted into the 'last' position in the queue.

This is not correct. The implementation treats a non existing key as the smallest possible value. The queue itself is in a smallest first order meaning a message without sorting key will be put at the head of the queue.

[1] http://qpid.apache.org/releases/qpid-0.32/java-broker/book/Java-Broker-Management-Managing-Queues.html#Java-Broker-Management-Managing-Queues-Types-Sorted