title: OpenJDK core dump from the command line?
body: <p>Can anyone give me a hint to what I am doing wrong?</p>
  
  <p>So, on Redhat (Amazon AMI Instance) , I am trying to get a core dump of my running application.  I am unable to connect to the JMX port from jconsole.exe or jvisualvm.exe from a windows box even though the remote port is wide open (and JMX server is properly configured).  I don't know why, and so I am trying to get a core dump from the JVM directly (Cntrl-\ didnt work).   So, here is how I set things up to get the core dump, but it doesn't work and I don't know why.</p>
  
  <pre><code>[ec2-user bin]$
  jsadebugd 2504 -F Attaching to process
  ID 2504 and starting RMI services,
  please wait... Debugger attached and
  RMI services started.
  </code></pre>
  
  <p>So, after the debugger is running, I try to create the dump using this, but it fails:</p>
  
  <pre><code>[ec2-user ~]$ jmap -dump:live,format=b,file=dump.t 2504 
  2504: Unable to open socket file:
  target process not responding or
  HotSpot VM not loaded The -F option
  can be used when the target process is
  not responding
  
  [ec2-user ~]$ jmap -dump:live,format=b,file=dump.t 2504 -F 
  Attaching to core -F from 
  executable 2504, please wait... Error
  attaching to core file: Can't attach
  to the core file
  </code></pre>