title: Spring-mvc using async controllers
body: <p>I'm creating a spring-mvc restful app, and I'm questionning about performance when it gonna be on production.</p>
  
  <p>I found this <a href="https://spring.io/blog/2012/05/07/spring-mvc-3-2-preview-introducing-servlet-3-async-support" rel="nofollow noreferrer">link</a> about async controllers, but I still have few questions. In general, what happens when 3 clients try to access a page?
  Is this async or synchronous that is to say, <strong>I)</strong> client A will be processed, then B, and then C, like a waiting queue, or <strong>II)</strong> do they have a different and single thread each?</p>
  
  <p>If <strong>I)</strong>, would I have to make all my controllers aync?</p>