Java 如何查看线程死锁的工具【jps】【jstack】

﹏ヽ暗。殇╰゛Y 2023-07-05 05:22 13阅读 0赞

下面部分内容摘自：《Java多线程编程核心技术》.pdf

# 死锁定义 #

![20200213111744379.png][]

# 创建项目和线程类 #

![20200213111842907.png][]

package chapter02.section02.thread_2_2_12.project_1_deadLockTest;
    
    public class DealThread implements Runnable {
    
    	public String username;
    	public Object lock1 = new Object();
    	public Object lock2 = new Object();
    
    	public void setFlag(String username) {
    		this.username = username;
    	}
    
    	@Override
    	public void run() {
    		if (username.equals("a")) {
    			synchronized (lock1) {
    				try {
    					System.out.println("username = " + username);
    					Thread.sleep(3000);
    				} catch (InterruptedException e) {
    					// TODO Auto-generated catch block
    					e.printStackTrace();
    				}
    				synchronized (lock2) {
    					System.out.println("按lock1->lock2代码顺序执行了");
    				}
    			}
    		}
    		if (username.equals("b")) {
    			synchronized (lock2) {
    				try {
    					System.out.println("username = " + username);
    					Thread.sleep(3000);
    				} catch (InterruptedException e) {
    					// TODO Auto-generated catch block
    					e.printStackTrace();
    				}
    				synchronized (lock1) {
    					System.out.println("按lock2->lock1代码顺序执行了");
    				}
    			}
    		}
    	}
    
    }

# 创建运行类 #

![20200213111921845.png][]

package chapter02.section02.thread_2_2_12.project_1_deadLockTest;
    
    public class Run {
    	public static void main(String[] args) {
    		try {
    			DealThread t1 = new DealThread();
    			t1.setFlag("a");
    
    			Thread thread1 = new Thread(t1);
    			thread1.start();
    
    			Thread.sleep(100);
    
    			t1.setFlag("b");
    			Thread thread2 = new Thread(t1);
    			thread2.start();
    		} catch (InterruptedException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    	}
    }

# 运行结果：出现死锁 #

![20200213112006493.png][]

![20200213112142508.png][]

# jps命令 #

jps

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pwMzU3MjUyNTM5_size_16_color_FFFFFF_t_70][]

![20200213112321704.png][]

# jstack命令 #

jstack -l 18776

C:\program\Java\jdk1.6.0_45\bin>jstack -l 18776
    2020-02-13 11:15:27
    Full thread dump Java HotSpot(TM) Client VM (20.45-b01 mixed mode, sharing):
    
    "DestroyJavaVM" prio=6 tid=0x00e6ac00 nid=0x40cc waiting on condition [0x00000000]
       java.lang.Thread.State: RUNNABLE
    
       Locked ownable synchronizers:
            - None
    
    "Thread-1" prio=6 tid=0x0255c000 nid=0x53c0 waiting for monitor entry [0x04d8f000]
       java.lang.Thread.State: BLOCKED (on object monitor)
            at chapter02.section02.thread_2_2_12.project_1_deadLockTest.DealThread.run(DealThread.java:39)
            - waiting to lock <0x2442c848> (a java.lang.Object)
            - locked <0x2442c850> (a java.lang.Object)
            at java.lang.Thread.run(Thread.java:662)
    
       Locked ownable synchronizers:
            - None
    
    "Thread-0" prio=6 tid=0x02517800 nid=0x8e8 waiting for monitor entry [0x04cff000]
       java.lang.Thread.State: BLOCKED (on object monitor)
            at chapter02.section02.thread_2_2_12.project_1_deadLockTest.DealThread.run(DealThread.java:25)
            - waiting to lock <0x2442c850> (a java.lang.Object)
            - locked <0x2442c848> (a java.lang.Object)
            at java.lang.Thread.run(Thread.java:662)
    
       Locked ownable synchronizers:
            - None
    
    "Low Memory Detector" daemon prio=6 tid=0x0250e800 nid=0x4ec0 runnable [0x00000000]
       java.lang.Thread.State: RUNNABLE
    
       Locked ownable synchronizers:
            - None
    
    "C1 CompilerThread0" daemon prio=10 tid=0x02520800 nid=0x5074 waiting on condition [0x00000000]
       java.lang.Thread.State: RUNNABLE
    
       Locked ownable synchronizers:
            - None
    
    "Monitor Ctrl-Break" daemon prio=6 tid=0x02521c00 nid=0x3864 runnable [0x04a7f000]
       java.lang.Thread.State: RUNNABLE
            at java.net.SocketInputStream.socketRead0(Native Method)
            at java.net.SocketInputStream.read(SocketInputStream.java:129)
            at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:264)
            at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:306)
            at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:158)
            - locked <0x2441b158> (a java.io.InputStreamReader)
            at java.io.InputStreamReader.read(InputStreamReader.java:167)
            at java.io.BufferedReader.fill(BufferedReader.java:136)
            at java.io.BufferedReader.readLine(BufferedReader.java:299)
            - locked <0x2441b158> (a java.io.InputStreamReader)
            at java.io.BufferedReader.readLine(BufferedReader.java:362)
            at com.intellij.rt.execution.application.AppMainV2$1.run(AppMainV2.java:64)
    
       Locked ownable synchronizers:
            - None
    
    "Attach Listener" daemon prio=10 tid=0x024ec000 nid=0x2378 waiting on condition [0x00000000]
       java.lang.Thread.State: RUNNABLE
    
       Locked ownable synchronizers:
            - None
    
    "Signal Dispatcher" daemon prio=10 tid=0x024eb000 nid=0x3620 runnable [0x00000000]
       java.lang.Thread.State: RUNNABLE
    
       Locked ownable synchronizers:
            - None
    
    "Finalizer" daemon prio=8 tid=0x024de000 nid=0x5690 in Object.wait() [0x048cf000]
       java.lang.Thread.State: WAITING (on object monitor)
            at java.lang.Object.wait(Native Method)
            - waiting on <0x243b1148> (a java.lang.ref.ReferenceQueue$Lock)
            at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118)
            - locked <0x243b1148> (a java.lang.ref.ReferenceQueue$Lock)
            at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134)
            at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:171)
    
       Locked ownable synchronizers:
            - None
    
    "Reference Handler" daemon prio=10 tid=0x024dcc00 nid=0x1ab4 in Object.wait() [0x0483f000]
       java.lang.Thread.State: WAITING (on object monitor)
            at java.lang.Object.wait(Native Method)
            - waiting on <0x243b1048> (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 <0x243b1048> (a java.lang.ref.Reference$Lock)
    
       Locked ownable synchronizers:
            - None
    
    "VM Thread" prio=10 tid=0x024a0800 nid=0x4a7c runnable
    
    "VM Periodic Task Thread" prio=10 tid=0x02516400 nid=0x48f0 waiting on condition
    
    JNI global references: 921
    
    
    Found one Java-level deadlock:
    =============================
    "Thread-1":
      waiting to lock monitor 0x024e3534 (object 0x2442c848, a java.lang.Object),
      which is held by "Thread-0"
    "Thread-0":
      waiting to lock monitor 0x024e296c (object 0x2442c850, a java.lang.Object),
      which is held by "Thread-1"
    
    Java stack information for the threads listed above:
    ===================================================
    "Thread-1":
            at chapter02.section02.thread_2_2_12.project_1_deadLockTest.DealThread.run(DealThread.java:39)
            - waiting to lock <0x2442c848> (a java.lang.Object)
            - locked <0x2442c850> (a java.lang.Object)
            at java.lang.Thread.run(Thread.java:662)
    "Thread-0":
            at chapter02.section02.thread_2_2_12.project_1_deadLockTest.DealThread.run(DealThread.java:25)
            - waiting to lock <0x2442c850> (a java.lang.Object)
            - locked <0x2442c848> (a java.lang.Object)
            at java.lang.Thread.run(Thread.java:662)
    
    Found 1 deadlock.
    
    
    C:\program\Java\jdk1.6.0_45\bin>j

# 在最后发现一个死锁 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pwMzU3MjUyNTM5_size_16_color_FFFFFF_t_70 1][]

[20200213111744379.png]: https://img-blog.csdnimg.cn/20200213111744379.png
[20200213111842907.png]: https://img-blog.csdnimg.cn/20200213111842907.png
[20200213111921845.png]: https://img-blog.csdnimg.cn/20200213111921845.png
[20200213112006493.png]: https://img-blog.csdnimg.cn/20200213112006493.png
[20200213112142508.png]: https://img-blog.csdnimg.cn/20200213112142508.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pwMzU3MjUyNTM5_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200213112242338.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pwMzU3MjUyNTM5,size_16,color_FFFFFF,t_70
[20200213112321704.png]: https://img-blog.csdnimg.cn/20200213112321704.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pwMzU3MjUyNTM5_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200213112515848.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pwMzU3MjUyNTM5,size_16,color_FFFFFF,t_70