jstack打印信息问题
我使用jstack打印了信息，信息的内容好像是线程出现了死锁，大家能帮我看下这个文件，到底是哪出了问题 ? ?
我看不懂这个文件。
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Full thread dump Java HotSpot(TM) 64-Bit Server VM (20.8-b03 mixed mode):
"catalina-exec-120" daemon prio=10 tid=0x000000005b293800 nid=0x7171 waiting on condition [0x0000000043b65000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x00000000c01e82a0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$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$Worker.run(ThreadPoolExecutor.java:907)
at java.lang.Thread.run(Thread.java:662)
"catalina-exec-119" daemon prio=10 tid=0x000000005b292000 nid=0x70ad waiting on condition [0x0000000043a64000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x00000000c01e82a0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
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)
"catalina-exec-118" daemon prio=10 tid=0x000000005b24a800 nid=0x6ff7 waiting on condition [0x0000000043963000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x00000000c01e82a0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$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$Worker.run(ThreadPoolExecutor.java:907)
at java.lang.Thread.run(Thread.java:662)
"catalina-exec-117" daemon prio=10 tid=0x000000005b248800 nid=0x6fb2 waiting on condition [0x0000000043862000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x00000000c01e82a0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
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)
"catalina-exec-116" daemon prio=10 tid=0x000000005af11000 nid=0x6f3d waiting on condition [0x0000000043761000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x00000000c01e82a0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$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)
[解决办法]
你这个信息并不能看出就一定是死锁。只不过是说很多现线程都在等待而已。
加个参数 L 再执行，类似：
jstack -l PID
然后看看最后面有无提示死锁。
另外，就算没有死锁，也不代表程序状态就一定正常。
比如：程序也许在等待网络输入，虽然没有死锁，但如果网络永远没有输入，程序也就永远等待了。
