java--怎样使用jstack诊断Java应用程序故障

查询CPU暂用过高的用法：
1，使用jps查找出java进程的pid，如3707
2，使用top -p 3707观察进程情况，然后Shift+h,显示该进程的所有线程。
3，找出CPU消耗较多的线程id，如3720，将3720转换为16进制0x7d0，注意是小写哦
4，使用jstack 3707 | grep -A 10 0x7d0 来查询出具体的线程状态。
内容摘自：http://wolfcame.iteye.com/blog/1770470

 /**
  * 死锁例子
  * @author crane.ding
  * @since 2011-3-20
  */
 public class DeadLock {

     public static void main(String[] args) {
         final Object obj_1 = new Object(), obj_2 = new Object();

         Thread t1 = new Thread("t1"){
             @Override
             public void run() {
                 synchronized (obj_1) {
                     try {
                         Thread.sleep(3000);
                     } catch (InterruptedException e) {}

                     synchronized (obj_2) {
                         System.out.println("thread t1 done.");
                     }
                 }
             }
         };

         Thread t2 = new Thread("t2"){
             @Override
             public void run() {
                 synchronized (obj_2) {
                     try {
                         Thread.sleep(3000);
                     } catch (InterruptedException e) {}

                     synchronized (obj_1) {
                         System.out.println("thread t2 done.");
                     }
                 }
             }
         };

         t1.start();
         t2.start();
     }

 }

        以上DeadLock类是一个死锁的例子,假使在我们不知情的情况下,运行DeadLock后,发现等了N久都没有在屏幕打印线程完成信息。这个时候我们就可以使用jps查看该程序的jpid值和使用jstack来生产堆栈结果问题。  

 $ java -cp deadlock.jar DeadLock &
 $

 $ jps
   3076 Jps
   448 DeadLock
 $ jstack -l 448 > deadlock.jstack

结果文件deadlock.jstack内容如下： 

 2011-03-20 23:05:20
 Full thread dump Java HotSpot(TM) Client VM (19.1-b02 mixed mode, sharing):

 "DestroyJavaVM" prio=6 tid=0x00316800 nid=0x9fc waiting on condition [0x00000000]
    java.lang.Thread.State: RUNNABLE

    Locked ownable synchronizers:
     - None

 "t2" prio=6 tid=0x02bcf000 nid=0xc70 waiting for monitor entry [0x02f6f000]
    java.lang.Thread.State: BLOCKED (on object monitor)
     at com.demo.DeadLock$2.run(DeadLock.java:40)
     - waiting to lock <0x22a297a8> (a java.lang.Object)
     - locked <0x22a297b0> (a java.lang.Object)

    Locked ownable synchronizers:
     - None

 "t1" prio=6 tid=0x02bce400 nid=0xba0 waiting for monitor entry [0x02f1f000]
    java.lang.Thread.State: BLOCKED (on object monitor)
     at com.demo.DeadLock$1.run(DeadLock.java:25)
     - waiting to lock <0x22a297b0> (a java.lang.Object)
     - locked <0x22a297a8> (a java.lang.Object)

    Locked ownable synchronizers:
     - None

 "Low Memory Detector" daemon prio=6 tid=0x02bb9400 nid=0xa6c runnable [0x00000000]
    java.lang.Thread.State: RUNNABLE

    Locked ownable synchronizers:
     - None

 "CompilerThread0" daemon prio=10 tid=0x02bb2800 nid=0xcb8 waiting on condition [0x00000000]
    java.lang.Thread.State: RUNNABLE

    Locked ownable synchronizers:
     - None

 "Attach Listener" daemon prio=10 tid=0x02bb1000 nid=0x7f4 waiting on condition [0x00000000]
    java.lang.Thread.State: RUNNABLE

    Locked ownable synchronizers:
     - None

 "Signal Dispatcher" daemon prio=10 tid=0x02bd2800 nid=0xd80 runnable [0x00000000]
    java.lang.Thread.State: RUNNABLE

    Locked ownable synchronizers:
     - None

 "Finalizer" daemon prio=8 tid=0x02bab000 nid=0xe1c in Object.wait() [0x02d3f000]
    java.lang.Thread.State: WAITING (on object monitor)
     at java.lang.Object.wait(Native Method)
     - waiting on <0x229e1148> (a java.lang.ref.ReferenceQueue$Lock)
     at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118)
     - locked <0x229e1148> (a java.lang.ref.ReferenceQueue$Lock)
     at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134)
     at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:159)

    Locked ownable synchronizers:
     - None

 "Reference Handler" daemon prio=10 tid=0x02ba6800 nid=0xbe0 in Object.wait() [0x02cef000]
    java.lang.Thread.State: WAITING (on object monitor)
     at java.lang.Object.wait(Native Method)
     - waiting on <0x229e1048> (a java.lang.ref.Reference$Lock)
     at java.lang.Object.wait(Object.java:485)
     at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:116)
     - locked <0x229e1048> (a java.lang.ref.Reference$Lock)

    Locked ownable synchronizers:
     - None

 "VM Thread" prio=10 tid=0x02b6a400 nid=0x568 runnable

 "VM Periodic Task Thread" prio=10 tid=0x02bc8400 nid=0x75c waiting on condition

 JNI global references: 878


 Found one Java-level deadlock:
 =============================
 "t2":
   waiting to lock monitor 0x02baaeec (object 0x22a297a8, a java.lang.Object),
   which is held by "t1"
 "t1":
   waiting to lock monitor 0x02baa2bc (object 0x22a297b0, a java.lang.Object),
   which is held by "t2"

 Java stack information for the threads listed above:
 ===================================================
 "t2":
     at com.demo.DeadLock$2.run(DeadLock.java:40)
     - waiting to lock <0x22a297a8> (a java.lang.Object)
     - locked <0x22a297b0> (a java.lang.Object)
 "t1":
     at com.demo.DeadLock$1.run(DeadLock.java:25)
     - waiting to lock <0x22a297b0> (a java.lang.Object)
     - locked <0x22a297a8> (a java.lang.Object)

 Found 1 deadlock.