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copied!<p>The Spring MVC part of your question is rather easy, since the problem has nothing to do with Spring MVC. See a possible solution in this answer: <a href="https://stackoverflow.com/a/4427922/734687">https://stackoverflow.com/a/4427922/734687</a></p> <p>As you can see in the code, the author is using a tokenService to store the future. The implementation is not included and here the problems begin, as you are already aware of, when you want failover.</p> <ul> <li>It is not possible to serialize the future and let it jump to a second server instance. The thread is executed within a certain instance and therefore has to stay there. So session storage is no option.</li> <li>As in the example link you could use a token service. This is normally just a HashMap where you can store your object and access it later again via the token (the String identifier). But again, this works only within the same web application, when the tokenService is a singleton.</li> </ul> <p>The solution is not to save the future, but instead the state of the work (in work, finished, failed with result). Even when the querying session and the executing threads are on different machines, the state should be accessible and serialize able. But how would you do that? This could be implemented by storing it in a database or on the file system (the example above you could check if the zip file is available) or in a key/value store or in a cache or in a common object store (Terracota), ...</p> <p>In fact, every batch framework (Spring Batch for example) works this way. It stores the current state of the jobs in the database. You are concerned that you mix domain data with operation data. But most applications do. On large applications there is the possibility to use two database instances, operational data and domain data.</p> <p>So I recommend that you save the state and the result of the work in a database.<br> Hope that helps.</p>

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