title: Eclipse debugger always blocks on ThreadPoolExecutor without any obvious exception, why?
body: <p>I'm working on my usual projects on Eclipse, it's a J2EE application, made with Spring, Hibernate and so on. I'm using Tomcat 7 for this (no particular reason, I don't exploit any new feature, I just wanted to try that). Every time I debug my application, it happens that Eclipse debugger pops out like it has reached a breakpoint, but it is not the case, in fact it stops on a Java source file that is <code>ThreadPoolExecutor</code>. There is no stack trace on the console, it just stops. Then if I click on resume it goes on and the app works perfectly. This is what shows in the debugger window:</p>
  
  <pre><code>Daemon Thread ["http-bio-8080"-exec-2] (Suspended (exception RuntimeException)) 
      ThreadPoolExecutor$Worker.run() line: 912   
      TaskThread(Thread).run() line: 619
  </code></pre>
  
  <p>I really can't explain this, because I'm not using <code>ThreadPoolExecutor</code> at all. Must be something from Tomcat, Hibernate or Spring. It's very annoying because I always have to resume during debugging.</p>
  
  <p>Any clues?</p>