.

 <p>
 <b>Message headers</b> Jakarta Messaging defines a number of message header fields and message properties which must be set by the
 "Jakarta Messaging provider on send". If the send is asynchronous these fields and properties may be accessed on the sending client
 only after the <tt>CompletionListener</tt> has been invoked. If the <tt>CompletionListener</tt>'s
 <tt>onException</tt> method is called then the state of these message header fields and properties is undefined.

 <p>
 <b>Restrictions on 