java 线程状态

最新推荐文章于 2024-04-04 12:46:33 发布

sam-fat-chang

最新推荐文章于 2024-04-04 12:46:33 发布

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分类专栏： java concurrency 文章标签： java 线程状态 java线程状态

本文链接：https://blog.youkuaiyun.com/u014783753/article/details/55100814

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java定义的线程状态：NEW/RUNNABLE/WAITING/TIMED_WAITING/BLOCKED/TERMINATED

java的线程方法使得线程的状态转换如下：

1 sleep RUNNING--->TIMED_WAITING

2 join RUNNING--->WAITING

3 wait RUNNING--->WAITING

4 yield RUNNING--->RUNNABLE 不一定，因为调用yield的当前线程有可能被cpu再次选中执行，这种情况那么线程此时的状态是RUNNING

5 notify WAITING --->BLOCKED

6 notifyAll WAITING ---->BLOCKED

7 synchronized RUNNING--->BLOCKED

验证以上其中情况，代码和stack信息如下：

situation1:

import java.util.concurrent.TimeUnit;

public class a
{
        public static void main(String[] args)
        {
                Runnable r = new b();
                Thread bT = new Thread(r);
                bT.setName("bT");
                bT.start();
                synchronized(r){
                        System.out.println(Thread.currentThread().getName());
                        try{
                                TimeUnit.SECONDS.sleep(60);
                        }catch(Exception e){
                                e.printStackTrace();
                        }
                }
        }

        static class b implements Runnable
        {
                public void run(){
                        synchronized(this){
                                System.out.println(Thread.currentThread().getName());
                                try{
                                        TimeUnit.SECONDS.sleep(60);
                                }catch(Exception e){
                                        e.printStackTrace();
                                }
                        }
                }
        }
}
~

jstack 输出如下：

2017-02-14 10:01:23
Full thread dump Java HotSpot(TM) 64-Bit Server VM (24.80-b11 mixed mode):

   java.lang.Thread.State: RUNNABLE

"bT" prio=10 tid=0x00007f3dc80b9000 nid=0x3028 waiting for monitor entry [0x00007f3dc13fb000]
   java.lang.Thread.State: BLOCKED (on object monitor)
        at a$b.run(a.java:26)
        - waiting to lock <0x00000007d704b910> (a a$b)
        at java.lang.Thread.run(Thread.java:745)

   java.lang.Thread.State: RUNNABLE

   java.lang.Thread.State: RUNNABLE

   java.lang.Thread.State: RUNNABLE

   java.lang.Thread.State: RUNNABLE

   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        - waiting on <0x00000007d7004858> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:135)
        - locked <0x00000007d7004858> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:151)
        at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:209)

   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        - waiting on <0x00000007d7004470> (a java.lang.ref.Reference$Lock)
        at java.lang.Object.wait(Object.java:503)
        at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:133)
        - locked <0x00000007d7004470> (a java.lang.ref.Reference$Lock)

"main" prio=10 tid=0x00007f3dc8008800 nid=0x3017 waiting on condition [0x00007f3dcc88a000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
        at java.lang.Thread.sleep(Native Method)
        at java.lang.Thread.sleep(Thread.java:340)
        at java.util.concurrent.TimeUnit.sleep(TimeUnit.java:360)
        at a.main(a.java:15)
        - locked <0x00000007d704b910> (a a$b)

"VM Thread" prio=10 tid=0x00007f3dc8071000 nid=0x3020 runnable

"GC task thread#0 (ParallelGC)" prio=10 tid=0x00007f3dc801e000 nid=0x3018 runnable

situation 2

import java.util.concurrent.TimeUnit;

public class f
{
        public static void main(String[] args)
        {
                Thread joinT = new Thread()
                {
                        public void run()
                        {
                                try
                                {
                                        for(int i = 0; i < Integer.MAX_VALUE;i++)
                                        {
                                                i++;
                                        }
                                }catch(Exception e)
                                {
                                        e.printStackTrace();
                                }//end try
                        }
                };//end Thread

                joinT.setName("joinT");
                joinT.start();
                try
                {
                        joinT.join();
                }catch(Exception e)
                {
                        e.printStackTrace();
                }

        }
}

jstack输出如下：

2017-02-14 15:09:08
Full thread dump Java HotSpot(TM) 64-Bit Server VM (24.80-b11 mixed mode):

   java.lang.Thread.State: RUNNABLE

"joinT" prio=10 tid=0x00007f86780b9000 nid=0x3a53 runnable [0x00007f866f0ef000]
   java.lang.Thread.State: RUNNABLE
        at f$1.run(f.java:15)

   java.lang.Thread.State: RUNNABLE

   java.lang.Thread.State: RUNNABLE

   java.lang.Thread.State: RUNNABLE

   java.lang.Thread.State: RUNNABLE

   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        - waiting on <0x00000007d7004858> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:135)
        - locked <0x00000007d7004858> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:151)
        at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:209)

   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        - waiting on <0x00000007d7004470> (a java.lang.ref.Reference$Lock)
        at java.lang.Object.wait(Object.java:503)
        at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:133)
        - locked <0x00000007d7004470> (a java.lang.ref.Reference$Lock)

"main" prio=10 tid=0x00007f8678008800 nid=0x3a42 in Object.wait() [0x00007f867e697000]
   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        - waiting on <0x00000007d704b0f0> (a f$1)
        at java.lang.Thread.join(Thread.java:1281)
        - locked <0x00000007d704b0f0> (a f$1)
        at java.lang.Thread.join(Thread.java:1355)
        at f.main(f.java:30)

"VM Thread" prio=10 tid=0x00007f8678071000 nid=0x3a4b runnable

"GC task thread#0 (ParallelGC)" prio=10 tid=0x00007f867801e000 nid=0x3a43 runnable

situation 3

import java.util.concurrent.TimeUnit;

public class b
{
        public static void main(String[] args)
        {
                Thread bt = new Thread()
                {
                        public void run()
                        {
                                synchronized(this)
                                {
                                        System.out.println(Thread.currentThread().getName());
                                        try
                                        {
                                                wait();
                                        }catch(Exception e)
                                        {
                                                e.printStackTrace();
                                        }
                                }
                        }
                };

                bt.setName("bt");
                bt.start();
                try
                {
                        TimeUnit.SECONDS.sleep(3);
                }catch(Exception e)
                {
                        e.printStackTrace();
                }
                synchronized(bt)
                {
                        System.out.println(Thread.currentThread().getName());
                        try
                        {
                                TimeUnit.SECONDS.sleep(30);
                        }catch(Exception e)
                        {
                                e.printStackTrace();
                        }
                        bt.notify();
                }
              }
}

jstack输出如下

2017-02-14 10:07:53
Full thread dump Java HotSpot(TM) 64-Bit Server VM (24.80-b11 mixed mode):

   java.lang.Thread.State: RUNNABLE

"bt" prio=10 tid=0x00007f73240b9000 nid=0x309c in Object.wait() [0x00007f731bdfc000]
   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        - waiting on <0x00000007d704b8a8> (a b$1)
        at java.lang.Object.wait(Object.java:503)
        at b$1.run(b.java:17)
        - locked <0x00000007d704b8a8> (a b$1)

   java.lang.Thread.State: RUNNABLE

   java.lang.Thread.State: RUNNABLE

   java.lang.Thread.State: RUNNABLE

   java.lang.Thread.State: RUNNABLE

   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        - waiting on <0x00000007d7004858> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:135)
        - locked <0x00000007d7004858> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:151)
        at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:209)

   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        - waiting on <0x00000007d7004470> (a java.lang.ref.Reference$Lock)
        at java.lang.Object.wait(Object.java:503)
        at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:133)
        - locked <0x00000007d7004470> (a java.lang.ref.Reference$Lock)

"main" prio=10 tid=0x00007f7324008800 nid=0x308b waiting on condition [0x00007f732b419000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
        at java.lang.Thread.sleep(Native Method)
        at java.lang.Thread.sleep(Thread.java:340)
        at java.util.concurrent.TimeUnit.sleep(TimeUnit.java:360)
        at b.main(b.java:40)
        - locked <0x00000007d704b8a8> (a b$1)

"VM Thread" prio=10 tid=0x00007f7324071000 nid=0x3094 runnable

situation 7

见：situation 1 的 bT状态