问题
I have a Ubuntu Server 10.10 64-bit running a web application on Jetty 6.1.24-6 on Sun's JVM, both installed from standard Ubuntu repositories.
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.
Unfortunately I'm unable to get the thread dump. I've tried to send a SIGQUIT to the process, and tried to attach JStack to it, but neither approach works.
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!
How can I obtain the thread dump?
回答1:
You have to do this as the same user as the jetty process is running under. On Ubuntu this user is normally called jetty.
So try
sudo -u jetty jstack <pid>
this will send a thread dump to stdout (your shell).
You can also
sudo -u jetty kill -QUIT <pid>
which will send the thread dump to jetty's stdout (normally /var/log/jetty/out.log)
To get the pids use the jps command or ps ax|grep java
回答2:
did you try VisualVM (/usr/lib/java-6-sun/bin/jvisualvm) with remote connection ? It can capture a thread dump
来源：https://stackoverflow.com/questions/6061302/how-to-get-jetty-thread-dump