<div dir="ltr">MK,<div><br></div><div>Thank you so much for your response. �I'm the amqp java api and create my service. �In my service, my main try/catch blockI establish the ConnectionFactory and Channel. �Then I assigned an executor service:</div>
<div>�channel.queueDeclare(QueueName, true, false, false, null);</div><div><span class="" style="white-space:pre"> </span>channel.basicConsume(strQueueName, false,</div><div><span class="" style="white-space:pre"> </span>new DefaultConsumer(channel) {</div>
<div><span class="" style="white-space:pre"> </span>@Override public void handleDelivery(String consumerTag,</div><div><span class="" style="white-space:pre"> </span>Envelope envelope,</div><div><span class="" style="white-space:pre"> </span>AMQP.BasicProperties props,</div>
<div><span class="" style="white-space:pre"> </span>byte[] body)</div><div><span class="" style="white-space:pre"> </span>throws IOException</div><div><span class="" style="white-space:pre"> </span>{}</div><div>
<br></div><div>If I understand it correctly, is the "handleDelivery" is like a listener on the queue. �Whenever a message arrives in the queue, everything inside the "handleDelivery" gets executed. �So, I have an object which invokes another service residing on the client application. �Based on your explaination, I have to ensure that the object is threaded because that's how the message is being dispatched to the client application. �The the object that I'm using isn't thread supported, then that'll explain the NPE(NullPointerException) within the "handleDelivery", right?</div>
<div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, Feb 7, 2014 at 12:05 PM, Michael Klishin <span dir="ltr"><<a href="mailto:michael.s.klishin@gmail.com" target="_blank">michael.s.klishin@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">
2014-02-07 17:55 GMT+04:00 cw storm <span dir="ltr"><<a href="mailto:cwstorm@gmail.com" target="_blank">cwstorm@gmail.com</a>></span>:<div class="im"><br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
Not sure I understand. �"Make sure your code is prepared for that." �What do you mean by that. �</blockquote><div><br></div></div><div>You instantiate Connection and Channel in one thread (often the main thread) but incoming messages</div>
<div>are dispatched from a different thread ("main loop" or "network I/O thread") into a pool every connection</div><div>has.</div><div><br></div><div>You need to make sure that the objects used in handleDelivery are initialized in a thread safe</div>
<div>manner (e.g. not lazily). A null pointer exception coming from handleDelivery suggests the problem</div><div>is with one of the objects you use there.</div><div class="im"><div>�</div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
Also, if thread pool, will it close once the broker receive a "basicAck"?</blockquote></div></div><br><div>If you did not provide a custom executor service to ConnectionFactory#newConnection, it will be</div><div>
shut down when connection is closed. Otherwise it's up to you to shut it down on application</div>
<div>shutdown.</div><span class=""><font color="#888888">-- <br>MK<br><br><a href="http://github.com/michaelklishin" target="_blank">http://github.com/michaelklishin</a><br><a href="http://twitter.com/michaelklishin" target="_blank">http://twitter.com/michaelklishin</a><br>
</font></span></div></div>
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