Java EE MDB using a local transaction Example

This example shows you how to send a message to an MDB and deliver it within a local transaction

The example will send deploy a simple MDB and demonstrate sending a message and the MDB consuming it, throwing an exception and the message being re delivered.

The example leverages the JBoss Arquillian framework to run a WildFly instance and deploy the MDB.

Example step-by-step

download WildFly 8.0.0.Final from here and install.

set the JBOSS_HOME property to point to the WildFly install directory

type mvn verify from the example directory to run

1. First we need to get an initial context so we can look-up the JMS connection factory and destination objects from JNDI. This initial context will get it's properties from the jndi.properties file in the directory config

           final Properties env = new Properties();

           env.put(Context.INITIAL_CONTEXT_FACTORY, "org.jboss.naming.remote.client.InitialContextFactory");

           env.put(Context.PROVIDER_URL, "http-remoting://localhost:8080");

           initialContext = new InitialContext(env);
        

2. We look up the JMS queue object from JNDI

           Queue queue = (Queue)initialContext.lookup("jms/queues/testQueue");
        

3. We look up the JMS connection factory object from JNDI

           ConnectionFactory cf = (ConnectionFactory)initialContext.lookup("/jms/RemoteConnectionFactory");
        

4. We create a JMS connection

           connection = cf.createConnection("guest", "password");
        

5. We create a JMS session. The session is created as non transacted and will auto acknowledge messages.

           Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
        

6. We create a JMS message producer on the session. This will be used to send the messages.

          MessageProducer messageProducer = session.createProducer(queue);
       

7. We create a JMS text messages that we are going to send.

            TextMessage message = session.createTextMessage("This is a text message");
        

8. We send messages to the queue

           messageProducer.send(message);
        

9. The MDB receives the message
   We know the message is a TextMessage so we cast to it.

           TextMessage tm = (TextMessage)message;
        

10. The MDB gets the text and prints it, we take a quick look at the transaction and throw an exception.

            System.out.println("message " + text + " received");

             if (!textMessage.getJMSRedelivered())
             {
                //Step 11. On first delivery get the transaction, take a look, and throw an exception
                Transaction tx = tm.getTransaction();

                if (tx != null)
                {
                   System.out.println("something is wrong, there should be no global transaction: " + tx);
                }
                else
                {
                   System.out.println("there is no global transaction, although the message delivery is using a local transaction");
                   System.out.println("let's throw an exception and see what happens");
                   throw new RuntimeException("DOH!");
                }
             }            
        

11. The MDB receives the message again and we print a message.

           System.out.println("The message was redelivered since the message delivery used a local transaction");
        

12. And finally, always remember to close your JMS connections and resources after use, in a finally block. Closing a JMS connection will automatically close all of its sessions, consumers, producer and browser objects

           finally
           {
              if (initialContext != null)
              {
                initialContext.close();
              }
              if (connection != null)
              {
                 connection.close();
              }
           }