JBoss JMS MessageConsumer waits indefinitely for response message - jboss

Question

I am trying to create a synchronous request using JMS on JBoss
Code for MDB is:
#Resource(mappedName = "java:/ConnectionFactory")
private ConnectionFactory connectionFactory;
#Override
public void onMessage(Message message) {
logger.info("Received message for client call");
if (message instanceof ObjectMessage) {
Connection con = null;
try {
con = connectionFactory.createConnection();
con.start();
Requests requests = (Requests) ((ObjectMessage) message)
.getObject();
String response = getClient().get(getRequest(requests));
con = connectionFactory.createConnection();
Session ses = con.createSession(true, Session.AUTO_ACKNOWLEDGE);
MessageProducer producer = ses.createProducer(message
.getJMSReplyTo());
TextMessage replyMsg = ses.createTextMessage();
replyMsg.setJMSCorrelationID(message.getJMSCorrelationID());
replyMsg.setText(response);
logger.info("Sending reply to client call : " + response );
producer.send(replyMsg);
} catch (JMSException e) {
logger.severe(e.getMessage());
} finally {
if (con != null) {
try {
con.close();
} catch (Exception e2) {
logger.severe(e2.getMessage());
}
}
}
}
}
Code for client is:
#Resource(mappedName = "java:/ConnectionFactory")
private QueueConnectionFactory queueConnectionFactory;
#Resource(mappedName = "java:/queue/request")
private Queue requestQueue;
#Override
public Responses getResponses(Requests requests) {
QueueConnection connection = null;
try {
connection = queueConnectionFactory.createQueueConnection();
connection.start();
QueueSession session = connection.createQueueSession(false,
Session.AUTO_ACKNOWLEDGE);
MessageProducer messageProducer = session
.createProducer(requestQueue);
ObjectMessage message = session.createObjectMessage();
message.setObject(requests);
TemporaryQueue temp = session.createTemporaryQueue();
MessageConsumer consumer = session.createConsumer(temp);
message.setJMSReplyTo(temp);
messageProducer.send(message);
Message response = consumer.receive();
if (response instanceof TextMessage) {
logger.info("Received response");
return new Responses(null, ((TextMessage) response).getText());
}
} catch (JMSException e) {
logger.severe(e.getMessage());
} finally {
if (connection != null) {
try {
connection.close();
} catch (Exception e2) {
logger.severe(e2.getMessage());
}
}
}
return null;
}
The message is received fine on the queue, the response message is created and the MessageProducer sends the response without issue, with no errors. However the consumer just sits and waits indefinitely. I have also tried creating a separate reply queue rather then using a temporary queue and the result is the same.
I am guessing that I am missing something basic with this set up but I cannot for the life of me see anything I am doing wrong.
There is no other code, the 2 things I have read on this that can cause problems is that the connection.start() isn't called or the repsonses are going to some other different receiver, which isn't happening here (as far as I know - there are no other messaging parts to the code outside of these classes yet)
So I guess my question is, should the above code work or am I missing some fundamental understanding of the JMS flow?

Answer 1

So..I persevered and I got it to work.
The answer is that when I create the session, the transacted attribute in both the client and the MDB had to be set to false:
Session ses = con.createSession(true, Session.AUTO_ACKNOWLEDGE);
had to be changed to:
Session ses = con.createSession(false, Session.AUTO_ACKNOWLEDGE);
for both client and server.

Answer 2

I know why now! I am effectively doing the below which is taken from the Oracle JMS documentation!
If you try to use a request/reply mechanism, whereby you send a message and then try to receive a reply to the sent message in the same transaction, the program will hang, because the send cannot take place until the transaction is committed. The following code fragment illustrates the problem:
// Don’t do this!
outMsg.setJMSReplyTo(replyQueue);
producer.send(outQueue, outMsg);
consumer = session.createConsumer(replyQueue);
inMsg = consumer.receive();
session.commit();