title: How to get Jetty thread dump?
body: <p>I have a <strong>Ubuntu Server 10.10 64-bit</strong> running a web application on <strong>Jetty 6.1.24-6</strong> on <strong>Sun's JVM</strong>, both installed from standard Ubuntu repositories.</p>
  
  <p>I'm trying to track down a problem with this server (100% cpu after some time, it might be related to a known bug on NIO's Selector, although it looks like changing the connector to old io SocketConnector didn't solve the problem!), and need to take a thread dump.</p>
  
  <p>Unfortunately I'm unable to get the thread dump. I've tried to send a <strong>SIGQUIT</strong> to the process, and tried to attach <strong>JStack</strong> to it, but neither approach works.</p>
  
  <p>I see no output at all from SIGQUIT (in any of the log files generated by Jetty), and JStack, even when run as root (or jetty) and with "-F", says that it has been attached to the process, but then blocks and produces no more output!</p>
  
  <p>How can I obtain the thread dump?</p>