jstack $pid 可以打印出制定java程序的stack狀況。

將前邊top命令看到的執行緒id轉為16進位制顯示，就可以在jstack的結果中找到它了。

例如以下：
"pool-2-thread-1" prio=10 tid=0x000000004c9b2000 nid=0x11f4 waiting on condition [0x0000000042f36000]
   java.lang.Thread.State: WAITING (parking)
        at sun.misc.Unsafe.park(Native Method)
        - parking to wait for  <0x0000000580089050> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(LockSupport.java:158)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1987)
        at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:399)
        at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:947)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
        at java.lang.Thread.run(Thread.java:662)


其中的“nid=0x11f4 ”， 11f4就是執行緒id的16進製表示