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    <p><strong>Option 1</strong> is the easiest one, you can use there asynchronous EJB methods:</p> <p>SERVER</p> <pre><code>@Asynchronous public Future&lt;String&gt; getUpdatedModel() { //here create blocking process until something interesting happen return new AsyncResult&lt;String&gt;("model has changed!"); } </code></pre> <p>CLIENT</p> <pre><code> Future&lt;String&gt; updatedModel = bean.getUpdatedModel(); while(true){ String response = updatedModel.get(); //process response here } </code></pre> <p><strong>Option 2</strong> looks like option 1, but you have to take care of marshaling objects, so don't bother in using plain servlet.</p> <p><strong>Option 3</strong> looks interesting, as websockets are going to be included in Java EE7 (now you can use opensource comet implementations for servlets). In my opinion it is not designed for communication in enterprise applications, but might be fine for your usecase. There is a plenty of JSON serializers available (e.g. gson), I use that kind of communication between JS and java, and works fine.</p> <p><strong>Option 4</strong> breaks major Java EE principles (opening your own sockets is forbidden), and I would discourage you to use it.</p> <p><strong>Option 5</strong> Listen to Xie and use JMS! If you will use JMS topic, you could just send the message when particular event occur, and all connected client will receive the message asynchronously. It is natural Java EE way of solving this kind of problems, with out of box transactions, message redelivery and persistence if nessesary.</p>
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    1. POHow to send events (push notifications) from a Java EE application?
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    1. POHow to send events (push notifications) from a Java EE application?
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    1. COThanks for the extensive answer. I agree on most aspects but I have a minor problem... I just tried a "small" client prototype which resulted in a huge (MB) client application. I'm using Glassfish 3.1.2. on the the server side and the only way to get everything to work was to include a lot of glassfish jars ([link](http://stackoverflow.com/questions/4311157/glassfish-v3-x-and-remote-standalone-client/5745860#5745860) and [link](http://stackoverflow.com/questions/5675024/with-which-maven-dependencies-can-i-create-a-standalone-jms-client-for-glassfish/5745837#5745837)). Maybe I'll try 2) and 3)?
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    2. COJust expose those EJB as a SOAP WebService, client will be thinner and you still won't have to deal with serialization. If you do so, remove '@Asynchronous' annotations from EJB, as they are no supported with '@WebService' annotation.
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    3. COYou don't think the SOAP xml stuff is too much overhead for polling updates from multiple clients every second? I think I'll try at least the REST approach and maybe use protocol buffers for serialization.
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