title: Why is creating a Thread said to be expensive?
body: <p>The Java tutorials say that creating a Thread is expensive. But why exactly is it expensive? What exactly is happening when a Java Thread is created that makes its creation expensive? I'm taking the statement as true, but I'm just interested in mechanics of Thread creation in JVM. </p>
  
  <blockquote>
    <p>Thread lifecycle overhead. Thread creation and teardown are not free. The actual overhead varies across platforms, but thread creation takes time, introducing latency into request processing, and requires some processing activity by the JVM and OS. If requests are frequent and lightweight, as in most server applications, creating a new thread for each request can consume significant computing resources.</p>
  </blockquote>
  
  <p>From <em>Java Concurrency in Practice</em><br>
  By Brian Goetz, Tim Peierls, Joshua Bloch, Joseph Bowbeer, David Holmes, Doug Lea<br>
  Print ISBN-10: 0-321-34960-1</p>