title: What happens when creating a Thread instance, Java
body: <p>I have a questions about Java thread and OS thread, and I read <a href="https://stackoverflow.com/questions/5269535/java-threads-vs-pthreads">Java Threads vs Pthreads</a> and <a href="https://stackoverflow.com/questions/4427398/java-threads-vs-os-threads">Java Threads vs OS Threads</a> but I does not find an answer to my confusions.</p>
  
  <p>I had considered before we call start(), no OS thread is created .</p>
  
  <p>But according to <a href="https://docs.oracle.com/javase/7/docs/api/java/lang/Thread.State.html" rel="nofollow noreferrer">https://docs.oracle.com/javase/7/docs/api/java/lang/Thread.State.html</a> , </p>
  
  <blockquote>
    <p>A <strong>thread</strong> that has not yet started is in <code>NEW</code> state.</p>
  </blockquote>
  
  <p>Am I wrong or the states defined at java doc are not only to mark the state of Thread instance?</p>
  
  <p>My question is :</p>
  
  <ul>
  <li>what exactly happens when we create a Thread instance but before calling <code>start()</code></li>
  <li>when does a OS thread really created in Java</li>
  </ul>