Active mq - reading few times the same message

Question

Hi, i've got a question (problem?) about active mg. Firstly, i must admit that i'm a newbie to JMS.
ok, so i wrote 2 threads - one for reading messages, second for sending them. The thread for sending, sends only one (test) message and it finishes. the problem is, that the thread for reading (which connects, reads, sleeps for 15sec, connects, reads, sleeps for 15sec and so on)- reads the message few times.. I do not know what is the rule-should i read something (what?) to check if this message was already read by me? Or maybe i do not properly understand how it should works, or maybe i've got a problem in my code?:
public void run() {
      while (state) {
         receiveMessages();
         try {
            Thread.sleep(sleepTime);
         } catch (InterruptedException inex) {
            inex.printStackTrace();
   public void onMessage(Message message) {
      if (message instanceof TextMessage) {
         TextMessage textMessage = (TextMessage) message;
         System.out.println("Received message:\n" + textMessage);
   public synchronized void onException(JMSException jmsex) {
      System.out.println("JMSException");
      System.err.println(jmsex);
   protected void receiveMessages() {
      System.out.println("Connecting to URL " + url);
      ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory(url);
      try {
         connection = connectionFactory.createConnection();
         connection.setExceptionListener(this);
         connection.start();
         /* create the session */
         session = connection.createSession(transacted, Session.AUTO_ACKNOWLEDGE);
         destination = session.createQueue(subject);
         replyProducer = session.createProducer(destination);
         replyProducer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);
         consumer = session.createConsumer(destination);
         consumer.setMessageListener(this);
         if(transacted){
            session.commit();
      }catch(RejectedExecutionException rejex){
         System.out.println(rejex);
      catch (JMSException jmsex) {
         System.out.println(jmsex);
      } catch (UnsupportedOperationException unex) {
         unex.printStackTrace();
      } finally {
         if (consumer != null) {
            try {
               consumer.close();
            } catch (JMSException jmsex) {
               jmsex.printStackTrace();
         if (session != null) {
            try {
               session.close();
            } catch (JMSException jmsex) {
               System.err.println(jmsex);
               jmsex.printStackTrace();
         if (connection != null) {
            try {
               connection.close();
            } catch (JMSException jmsex) {
               System.err.println(jmsex);
               jmsex.printStackTrace();
      }for example, the result of executing this thread (remember that there was only 1 message sent):
Connecting to URL failover://tcp://localhost:61616
- Successfully connected to tcp://localhost:61616
Connecting to URL failover://tcp://localhost:61616
- Successfully connected to tcp://localhost:61616
Connecting to URL failover://tcp://localhost:61616
- Successfully connected to tcp://localhost:61616
Connecting to URL failover://tcp://localhost:61616
- Successfully connected to tcp://localhost:61616
Connecting to URL failover://tcp://localhost:61616
- Successfully connected to tcp://localhost:61616
Connecting to URL failover://tcp://localhost:61616
- Successfully connected to tcp://localhost:61616
Connecting to URL failover://tcp://localhost:61616
- Successfully connected to tcp://localhost:61616
Connecting to URL failover://tcp://localhost:61616
- Successfully connected to tcp://localhost:61616
Connecting to URL failover://tcp://localhost:61616
- Successfully connected to tcp://localhost:61616
Received message:
ActiveMQTextMessage {commandId = 6, responseRequired = false, messageId = ID:ppm-55786-1276257991972-0:0:1:1:1, originalDestination = null, originalTransactionId = null, producerId = ID:ppm-55786-1276257991972-0:0:1:1, destination = queue://ABC0, transactionId = TX:ID:ppm-55786-1276257991972-0:0:1, expiration = 0, timestamp = 1276257992758, arrival = 0, brokerInTime = 1276257992760, brokerOutTime = 1276258333378, correlationId = null, replyTo = null, persistent = true, type = null, priority = 4, groupID = null, groupSequence = 0, targetConsumerId = null, compressed = false, userID = null, content = null, marshalledProperties = null, dataStructure = null, redeliveryCounter = 16, size = 0, properties = null, readOnlyProperties = true, readOnlyBody = true, droppable = false, text = First ActiveMQ message}
Connecting to URL failover://tcp://localhost:61616
- Successfully connected to tcp://localhost:61616
Connecting to URL failover://tcp://localhost:61616
- Successfully connected to tcp://localhost:61616
Received message:
ActiveMQTextMessage {commandId = 6, responseRequired = false, messageId = ID:ppm-55786-1276257991972-0:0:1:1:1, originalDestination = null, originalTransactionId = null, producerId = ID:ppm-55786-1276257991972-0:0:1:1, destination = queue://ABC0, transactionId = TX:ID:ppm-55786-1276257991972-0:0:1, expiration = 0, timestamp = 1276257992758, arrival = 0, brokerInTime = 1276257992760, brokerOutTime = 1276258353773, correlationId = null, replyTo = null, persistent = true, type = null, priority = 4, groupID = null, groupSequence = 0, targetConsumerId = null, compressed = false, userID = null, content = null, marshalledProperties = null, dataStructure = null, redeliveryCounter = 18, size = 0, properties = null, readOnlyProperties = true, readOnlyBody = true, droppable = false, text = First ActiveMQ message}
Connecting to URL failover://tcp://localhost:61616
- Successfully connected to tcp://localhost:61616
Connecting to URL failover://tcp://localhost:61616
- Successfully connected to tcp://localhost:61616
Connecting to URL failover://tcp://localhost:61616
- Successfully connected to tcp://localhost:61616i do not understand why it has read the message in a nineth try! the message was already there-before i run this thread. why it took so long?
So it read the message, went sleeping, checked, went sleeping - and againg it read the message! why is that?
Can someone explain it to me? and suggest how should i do to read certain message only once?
thx and regards,
misty

Answer 1

Hi ..
Make sure your OS X software is up to date.
Click the Apple  top left in your screen.
From the drop down menu click Software Update
And try the troubleshooting steps for the built in iSight camera here >  How to Troubleshoot iSight