JVM的线程状态及如何排查死锁原因

一：线程状态：

操作系统的线程状态一共有：创建，就绪，运行，阻塞，死亡。

创建：生成线程对象，并未调用start()方法

就绪：调用thread.start()方法之后，线程还未被线程调度程序置为当前执行线程之前。

      或者线程在wait()时被notify后，或者sleep(1000)完成后。

          或者调用了线程的yield()方法后

运行：线程被线程调度程序置为当前执行线程

阻塞：线程wait()中或者sleep()中，或者等待某个锁

死亡：线程run()方法执行完毕;

 

二：jvm线程堆栈中的线程状态一共有以下：

1、TIMED_WAITING:出现在线程调用了wait(long)或者join(long)或sleep(long)的情况下

在线程堆栈中有两种常见表示：TIMED_WAITING (on object monitor)和TIMED_WAITING (sleeping)

2、WAITING：线程获得一个对象锁后，在该对象上等待其他线程来notify()

在线程堆栈中常见表示：WAITING (on object monitor)

3、BLOCKED：线程在等待临界资源被释放，比如等待另外一个线程释放临界资源

在线程堆栈中常见表示：BLOCKED (on object monitor)

4、RUNNABLE：当获得CPU的使用权时就可运行的线程，所以一次线程堆栈中可以有多个处于RUNNABLE状态的线程。该状态下，线程处于等待的原因，io,cpu时间片，而非锁，sleep().

在线程堆栈中常见表示：

java.lang.Thread.State: RUNNABLE

at java.net.SocketInputStream.socketRead0(Native Method)

        at java.net.SocketInputStream.read(SocketInputStream.java:129)

        at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)

        at java.io.BufferedInputStream.read(BufferedInputStream.java:237)

 

三：如何根据线程堆栈判断死锁：

根据死锁的原理，死锁原因可在BLOCKED状态的线程堆栈中找到原因。

如下例子：三个线程因等待不同的锁，处于BLOCKED状态，且A线程等待B线程持有的锁，B等待C持有的锁，而C又等待A持有的锁，造成锁的等待环，形成死锁。

 

1、线程"UCA_FINTERFACE ResponseListenerThread"，已获得锁<0x2b0c5b78>和<0x2b0dc348>和<0x14990288>，等待获取锁<0x14990230>，处在挂起状态

 

2、    线程"UCA_MAINFRAMESERVICE startupMonitor com.zte.ums.common.fm.wsf.mainframe.FmStartupMonitor"

    已获得锁<0x14990230>等待去获取锁<0x2b0c5b08>，

 

3、线程“UCA-FM:init client model”已获得锁<0x2b0c5b08>和<0x2b0c5ce0>，<0x2b0c5cf0>，等待锁<0x2b0c5b78>

 

线程1堆栈：

"UCA_FINTERFACE ResponseListenerThread" prio=10 tid=0x06438c00 nid=0x335e0 waiting for monitor entry [0x0869f000]

   java.lang.Thread.State: BLOCKED (on object monitor)

  at com.zte.ums.common.fm.wsf.msgservice.localdispatcher.LocalAlarmListenerManager.syncAlarmsFromLocalDB(LocalAlarmListenerManager.java:104)

        - waiting to lock <0x14990230> (a com.zte.ums.common.fm.wsf.msgservice.localdispatcher.LocalAlarmListenerManager)

        at com.zte.ums.common.fm.wsf.msgservice.localdispatcher.LocalSyncManager.syncAlarms(LocalSyncManager.java:86)

        at com.zte.ums.common.fm.wsf.dataprovider.AlarmDataProviderImpl.syncAlarmData(AlarmDataProviderImpl.java:213)

        - locked <0x2b0dc348> (a com.zte.ums.common.fm.wsf.dataprovider.AlarmDataProviderImpl)

        at com.zte.ums.common.fm.wsf.msgservice.AlarmListenerDecorator.syncAlarmData(AlarmListenerDecorator.java:144)

        - locked <0x2b0c5b78> (a com.zte.ums.common.fm.wsf.msgservice.AlarmListenerDecorator)

        at com.zte.ums.common.fm.wsf.msgservice.initalarmlistener.AlarmQueryFromServerRespListener.initListeners(AlarmQueryFromServerRespListener.java:146)

        at com.zte.ums.common.fm.wsf.msgservice.initalarmlistener.AlarmQueryFromServerRespListener.handleQueryResoponse(AlarmQueryFromServerRespListener.java:131)

        at com.zte.ums.common.fm.wsf.msgservice.initalarmlistener.AlarmQueryFromServerRespListener.onResponse(AlarmQueryFromServerRespListener.java:92)

        - locked <0x14990288> (a com.zte.ums.common.fm.wsf.msgservice.initalarmlistener.AlarmQueryFromServerRespListener)

        at com.zte.ums.uep.pfl.finterface.wsf.FServiceProxy$ResponseListenerProxy.onResponse(FServiceProxy.java:682)

        at com.zte.ums.uep.pfl.finterface.wsf.ResponseListenerThread.run(ResponseListenerThread.java:165)

                  

线程2堆栈：

         : "UCA_MAINFRAMESERVICE startupMonitor com.zte.ums.common.fm.wsf.mainframe.FmStartupMonitor" prio=10 tid=0x06677800 nid=0x2ec40 waiting for monitor entry [0x07d3f000]

   java.lang.Thread.State: BLOCKED (on object monitor)

        at com.zte.ums.common.fm.wsf.msgservice.AlarmModel.addAlarmListener(AlarmModel.java:93)

        - waiting to lock <0x2b0c5b08> (a com.zte.ums.common.fm.wsf.msgservice.AlarmModel)

        at com.zte.ums.common.fm.wsf.misc.sound.notifyrule.AlarmNotifyRuleAudioContinusPlayer.init(AlarmNotifyRuleAudioContinusPlayer.java:78)

        at com.zte.ums.common.fm.wsf.msgservice.AlarmNotifyRuleManager.init(AlarmNotifyRuleManager.java:117)

        at com.zte.ums.common.fm.wsf.msgservice.localdispatcher.LocalAlarmListenerManager.start(LocalAlarmListenerManager.java:48)

        - locked <0x14990230> (a com.zte.ums.common.fm.wsf.msgservice.localdispatcher.LocalAlarmListenerManager)

        at com.zte.ums.common.fm.wsf.mainframe.FmStartupMonitor.initUponServerStarted(FmStartupMonitor.java:69)

        at com.zte.ums.common.fm.wsf.mainframe.FmStartupMonitor.startedup(FmStartupMonitor.java:43)

        at com.zte.ums.uep.pfl.mainframe.main.control.WorkFlow$8$1$1.run(WorkFlow.java:1226)

        at java.lang.Thread.run(Thread.java:661)

线程3堆栈

"UCA-FM:init client model" prio=10 tid=0x065ed400 nid=0x3265c waiting for monitor entry [0x0793f000]

   java.lang.Thread.State: BLOCKED (on object monitor)

        at com.zte.ums.common.fm.wsf.msgservice.AlarmListenerDecorator.stop(AlarmListenerDecorator.java:91)

        - waiting to lock <0x2b0c5b78> (a com.zte.ums.common.fm.wsf.msgservice.AlarmListenerDecorator)

        at com.zte.ums.common.fm.wsf.msgservice.AlarmEventDispatcher.removeAllListener(AlarmEventDispatcher.java:169)

        - locked <0x2b0c5cf0> (a java.util.ArrayList)

        at com.zte.ums.common.fm.wsf.msgservice.AlarmEventDispatcher.stop(AlarmEventDispatcher.java:109)

        - locked <0x2b0c5ce0> (a com.zte.ums.common.fm.wsf.msgservice.AlarmEventDispatcher)

        at com.zte.ums.common.fm.wsf.msgservice.AlarmModel.stop(AlarmModel.java:75)

        - locked <0x2b0c5b08> (a com.zte.ums.common.fm.wsf.msgservice.AlarmModel)

        at com.zte.ums.common.fm.wsf.msgservice.AlarmModel.syncAlarms(AlarmModel.java:170)

        - locked <0x2b0c5b08> (a com.zte.ums.common.fm.wsf.msgservice.AlarmModel)

        at com.zte.ums.common.fm.wsf.msgservice.SyncAlarmManager.syncAlarms(SyncAlarmManager.java:112)

        at com.zte.ums.common.fm.wsf.misc.AlarmModelUpdateManager$1.run(AlarmModelUpdateManager.java:55)

        at java.lang.Thread.run(Thread.java:661)