Here’s how we do it programmatically: http://pastebin.com/uS5jYpd4 We use the JMX ThreadMXBean and ThreadInfo classes: ThreadMXBean mxBean = ManagementFactory.getThreadMXBean(); ThreadInfo[] threadInfos = mxBean.getThreadInfo(mxBean.getAllThreadIds(), 0); … You can also do a kill -QUIT pid under ~unix to dump the stacks to the standard-out. There is also jstack to dump the stack of a JVM. We also … Read more
Apparently the situation where we observed these kinds of blocked threads were related to heavy memory consumption and therefore massive garbage collection. This question Java blocking issue: Why would JVM block threads in many different classes/methods? describes a similar situation, so I believe these threads were simply blocked by the garbage collector. (Anyway, after solving … Read more
The TID is thead id and NID is: Native thread ID. This ID is highly platform dependent. It’s the NID in jstack thread dumps. On Windows, it’s simply the OS-level thread ID within a process. On Linux and Solaris, it’s the PID of the thread (which in turn is a light-weight process). On Mac OS … Read more
You can use jmap to get a dump of any process running, assuming you know the pid. Use Task Manager or Resource Monitor to get the pid. Then jmap -dump:format=b,file=heap.hprof <pid> to get the heap for that process. For systems where bash and pgrep are installed and a single Java process is running, try: jmap … Read more