Hawtio console becomes unresponsive when monitoring ActiveMQ, when an application uses null-destination message producers

Issue

An application creates null-destination JMS message producers; the relevant code is of the following form:

Session = // create session
Queue q = // create queue
while /*...*/)
  {
  MessageProducer p = session.createProducer (null); // no destination
  Message m = // create message
  p.send (q, m);  // destination specified here instead
  }

Notice that no destination is specified in the call to createProducer(). Instead, a destination is provided when the message is sent.

After a while, it will not be possible to monitor ActiveMQ operation using the Hawtio console -- the console will become slow and unresponsive. In the longer term, the broker may experience slow throughput and long garbage collection pauses, particularly with a large maximum heap size.