title: What is the default number of threads running in the JVM?
body: <p>Recently I've been learning more about thread and I was wondering why the resource monitor shows always 19 threads running for the Java process.</p>
  
  <p>Now my questions are:</p>
  
  <ul>
  <li>Is this the VM using 19 threads?</li>
  </ul>
  
  <p>If so:</p>
  
  <ul>
  <li>Are you able to access those threads?</li>
  <li>Is it possible to use these threads for thread pooling?</li>
  <li>Is it possible to decrease the amount of threads?</li>
  </ul>
  
  <p>If not:</p>
  
  <ul>
  <li>What is causing to show up the 19 threads?</li>
  </ul>
  
  <p>I created a small .jar (see bottom for source) that would run and create a fixed threadpool of 5 worker threads. To that pool I sent tasks and I noticed that after all tasks have been handled, the amount of threads java uses goes back to 19.</p>
  
  <p>Are the threads in the fixed threadpool idle or have they been removed and thus new threads are being created whenever new tasks are submitted?</p>
  
  <p>Sorry for the multiple questions in one post.</p>
  
  <ul>
  <li>Link to source: <a href="http://pastebin.com/iXpLbFVF" rel="nofollow">http://pastebin.com/iXpLbFVF</a></li>
  <li>Image while sending tasks: <a href="http://gyazo.com/223d720bf73c1b919fbfe0b69088838a" rel="nofollow">http://gyazo.com/223d720bf73c1b919fbfe0b69088838a</a></li>
  <li>Image after sending tasks: <a href="http://gyazo.com/3147269d90eb2c916373220ef53c0b92" rel="nofollow">http://gyazo.com/3147269d90eb2c916373220ef53c0b92</a></li>
  </ul>