Java Messaging Service - message not getting received

Question

I am writing a program using NetBeans IDE and Java EE with glassfish3 server. Currently I have 2 threads, A and B. They both are sending messages back and forth between eachother. The issue I am having is this:

1.  A sends a message, M1, to B
2.  B receives M1
3.  B sends M2 to A
4.  A hangs waiting on M2

Here is my code:

Thread A:

//required declarations
producer = session.createProducer(AtoBQueue);
m1 = session.createMapMessage();
m1.setString("m1", "m1Val");
m1.setJMSReplyTo(BtoAQueue);
flag = true;
producer.send(m1);

consumer = session.createConsumer(BtoAQueue);
connection.start();

if(flag){
   m2 = (MapMessage) consumer.receive();
   String m2Val = m2.getString("m2");
   if(m2Val.equals("true")){
      flag2 = true;
   }
}
...

Thread B:

consumer = session.createConsumer(AtoBQueue);
connection.start();
while(true){
   m1 = (MapMessage) consumer.receive();
   m1Val = m1.getString("m1");
   if(m1Val != null){
      flag = true;
   }

   MessageProducer producer = session.createProducer((Queue m1.getJMSReplyTo());
   m2 = session.createMapMessage();
   if(m1Val != null){
      if(m1Val.equals("m1Val")){
         m2.setString("m2", "m2Val");
         m2.setJMSReplyTo(AtoBQueue);
         producer.send(m2);
      }
   }
   ...
}

Answer 1

Turns out I needed to add in a session.commit() after I do a producer.send(message) only for Thread B.