title: Tomcat 7 Async Processing
body: <p>I am wondering how Tomcat 7 implements async processing. I understand that the request thread returns immediately, allowing the request thread to immediately listen for a new request and respond to it.</p>
  
  <p>How is the 'async' request handled? Is there a separate thread pool that handles async requests? I assume blocking IO is handled using something like java.nio.Selector for performance. What about threads that are blocking on CPU calculations? </p>