title: JMS: Can we get multiple messages from queue in OnMessage() withtout commit or rollback
body: <p>I am using a JMS client which receives JMS messages from a remote server. 
  I am listening to the JMS message in the onMessage() method of the client.</p>
  
  <p>The issue I am facing is that, messages are getting accumulated on the Server side even while I am consuming the messages on Client side at regular interval. </p>
  
  <p>I send a rollback() or commit() depending upon the processing I am doing on the client's end.</p>
  
  <p>I have a query that while I am processing the JMS message and I have not sent a commit() to the queue, can I get another message from the server.</p>
  
  <p>Please note that for the processing, I am doing a wait for the processing of the message received in a synchronized block.
  Will I get a new message while I am still processing and I have not sent a commit to the queue?</p>