You can see the source to jstack here. The -F argument changes how jstack connects to the jvm. With -F (or -m) JStack connects to the jvm using the java debugger interface. If a pid is specified, JStack connects with the SA PID Attaching Connector which says, The process to be debugged need not have … Read more
I got it working by doing two things: Changed call to: sudo -u tomcat6 jstack -J-d64 -m pid Replaced OpenJDK with Sun’s original sun-6-jdk and sun-6-jre packages Explanation for part 1: I switched to 64-bit mode, used sudo and run the command as Tomcat user. Note: Part 2 might not be necessary. For some users … Read more
This is probably due to the file in /tmp used to communicate with the process having different permissions than the one the jstack gets. The file in question is /tmp/hsperfdata_$USER/$PID. Don’t know why it works with -F as the man page just says “Force a stack dump when ‘jstack [-l] pid’ does not respond.”