title: HTMLUNIT v. 2.15 Bug Thread deadlock
body: <p>I'm using <strong>htmlunit (version 2.15)</strong>; I noticed a memory leak issue with the WebClient class: all webClient instances are not cleaned by garbage collector.</p>
  
  <p>The issue seems caused by threads deadlock:   </p>
  
  <pre><code>JavaScriptExecutor.run(JavaScriptExecutor.java:182)
  </code></pre>
  
  <p>I tried to call <strong>webclient.closeAllWindows</strong> for each instance but doesn't work.<br>
  I'm sure that <strong>ALL</strong> references to webClient objects are deallocated.  </p>
  
  <p>How can i properly <strong>clean</strong> the memory from webClient objects to avoid OOM? Garbage collector can't delete webClient objects due to thread lock.<br>
  I googled for hours but I don't find any working solution.<br>
  Thanks.</p>