jstack——打印 JVM 中线程快照

超、凢脫俗 2022-09-07 06:12 396阅读 0赞

## 一 点睛 ##

jstack（JVM Stack Trace）：用于生成虚拟机指定进程当前时刻的线程快照（虚拟机堆栈跟踪）。线程快照就是当前虚拟机内指定进程的每一条线程正在执行的方法堆栈的集合。

生成线程快照的作用：可用于定位线程出现长时间停顿的原因，如线程间死锁、死循环、请求外部资源导致的长时间等待等问题。这些都是导致线程长时间停顿的常见原因。当线程出现停顿时，就可以用 jstack 显示各个线程调用的堆栈情况。

官方帮助文档：[https://docs.oracle.com/en/java/javase/11/tools/jstack.html][https_docs.oracle.com_en_java_javase_11_tools_jstack.html]

在 thread dump 中，要留意下面几种状态

*  死锁，Deadlock（重点关注）
 *  等待资源，Waiting on condition（重点关注）
 *  等待获取监视器，Waiting on monitor entry（重点关注）
 *  阻塞，Blocked（重点关注）
 *  执行中，Runnable
 *  暂停，Suspended
 *  对象等待中，Object.wait() 或 TIMED＿WAITING
 *  停止，Parked

> F:\\svn\\19\_byzb\_back\\branches\\JVMDemo3>jstack
> 
> Usage:
> 
>     jstack \[-l\] <pid>
> 
>         (to connect to running process)
> 
>     jstack -F \[-m\] \[-l\] <pid>
> 
>         (to connect to a hung process)
> 
>     jstack \[-m\] \[-l\] <executable> <core>
> 
>         (to connect to a core file)
> 
>     jstack \[-m\] \[-l\] \[server\_id@\]<remote server IP or hostname>
> 
>         (to connect to a remote debug server)
> 
> Options:
> 
>     -F  to force a thread dump. Use when jstack <pid> does not respond (process is hung)
> 
>     -m  to print both java and native frames (mixed mode)
> 
>     -l  long listing. Prints additional information about locks
> 
>     -h or -help to print this help message

<table> 
 <tbody> 
  <tr> 
   <td> <p>option 参数</p> </td> 
   <td> <p>作用</p> </td> 
  </tr> 
  <tr> 
   <td> <p>-F</p> </td> 
   <td> <p>当正常输出的请求不被响应时，强制输出线程堆栈</p> </td> 
  </tr> 
  <tr> 
   <td> <p>-l</p> </td> 
   <td> <p>除堆栈外，显示关于锁的附加信息</p> </td> 
  </tr> 
  <tr> 
   <td> <p>-m</p> </td> 
   <td> <p>如果调用本地方法的话，可以显示 C/C++的堆栈</p> </td> 
  </tr> 
 </tbody> 
</table>

# 二 实战——定位死锁问题 #

## 1 代码 ##

package chaper02;
    
    /**
    * @className: ThreadDeadLock
    * @description: 线程死锁
    * @date: 2021/8/22
    */
    public class ThreadDeadLock {
        public static void main(String[] args) {
            StringBuilder s1 = new StringBuilder();
            StringBuilder s2 = new StringBuilder();
            new Thread() {
                public void run() {
                    synchronized (s1) {
                        s1.append("a");
                        s2.append("1");
    
                        try {
                            Thread.sleep(100);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
    
                        synchronized (s2) {
                            s1.append("b");
                            s2.append("2");
    
                            System.out.println(s1);
                            System.out.println(s2);
                        }
                    }
                }
            }.start();
    
            new Thread() {
                public void run() {
                    synchronized (s2) {
                        s1.append("c");
                        s2.append("3");
    
                        try {
                            Thread.sleep(100);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
    
                        synchronized (s1) {
                            s1.append("d");
                            s2.append("4");
                            System.out.println(s1);
                            System.out.println(s2);
                        }
                    }
                }
            }.start();
        }
    }

## 2 测试 ##

> F:\\svn\\19\_byzb\_back\\branches\\JVMDemo3>jstack 16324
> 
> 2021-08-22 15:45:20
> 
> Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.251-b08 mixed mode):
> 
> "DestroyJavaVM" \#14 prio=5 os\_prio=0 tid=0x00000000024ee800 nid=0x4d04 waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "Thread-1" \#13 prio=5 os\_prio=0 tid=0x000000001dd12000 nid=0x3efc waiting for monitor entry \[0x000000001ec6f000\]
> 
>    java.lang.Thread.State: BLOCKED (on object monitor)
> 
>         at chaper02.ThreadDeadLock$2.run(ThreadDeadLock.java:48)
> 
>         - waiting to lock <0x00000007708001a8> (a java.lang.StringBuilder)
> 
>         - locked <0x00000007708001f0> (a java.lang.StringBuilder)
> 
> "Thread-0" \#12 prio=5 os\_prio=0 tid=0x000000001dd0f000 nid=0x4874 waiting for monitor entry \[0x000000001eb6f000\]
> 
>    java.lang.Thread.State: BLOCKED (on object monitor)
> 
>         at chaper02.ThreadDeadLock$1.run(ThreadDeadLock.java:25)
> 
>         - waiting to lock <0x00000007708001f0> (a java.lang.StringBuilder)
> 
>         - locked <0x00000007708001a8> (a java.lang.StringBuilder)
> 
> "Service Thread" \#11 daemon prio=9 os\_prio=0 tid=0x000000001dcfa800 nid=0x3a5c runnable \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "C1 CompilerThread3" \#10 daemon prio=9 os\_prio=2 tid=0x000000001dc53000 nid=0x4fd4 waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "C2 CompilerThread2" \#9 daemon prio=9 os\_prio=2 tid=0x000000001dc52800 nid=0x4db4 waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "C2 CompilerThread1" \#8 daemon prio=9 os\_prio=2 tid=0x000000001dc4f000 nid=0x445c waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "C2 CompilerThread0" \#7 daemon prio=9 os\_prio=2 tid=0x000000001dc3d800 nid=0x1fa0 waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "Monitor Ctrl-Break" \#6 daemon prio=5 os\_prio=0 tid=0x000000001dc2b000 nid=0x1730 runnable \[0x000000001e46e000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
>         at java.net.SocketInputStream.socketRead0(Native Method)
> 
>         at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
> 
>         at java.net.SocketInputStream.read(SocketInputStream.java:171)
> 
>         at java.net.SocketInputStream.read(SocketInputStream.java:141)
> 
>         at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:284)
> 
>         at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:326)
> 
>         at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
> 
>         - locked <0x00000007706f2d58> (a java.io.InputStreamReader)
> 
>         at java.io.InputStreamReader.read(InputStreamReader.java:184)
> 
>         at java.io.BufferedReader.fill(BufferedReader.java:161)
> 
>         at java.io.BufferedReader.readLine(BufferedReader.java:324)
> 
>         - locked <0x00000007706f2d58> (a java.io.InputStreamReader)
> 
>         at java.io.BufferedReader.readLine(BufferedReader.java:389)
> 
>         at com.intellij.rt.execution.application.AppMainV2$1.run(AppMainV2.java:61)
> 
> "Attach Listener" \#5 daemon prio=5 os\_prio=2 tid=0x000000001dc00800 nid=0xbc8 waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "Signal Dispatcher" \#4 daemon prio=9 os\_prio=2 tid=0x000000001dbac000 nid=0x738 runnable \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "Finalizer" \#3 daemon prio=8 os\_prio=1 tid=0x000000001db91000 nid=0x4248 in Object.wait() \[0x000000001e16e000\]
> 
>    java.lang.Thread.State: WAITING (on object monitor)
> 
>         at java.lang.Object.wait(Native Method)
> 
>         - waiting on <0x0000000770588ee0> (a java.lang.ref.ReferenceQueue$Lock)
> 
>         at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144)
> 
>         - locked <0x0000000770588ee0> (a java.lang.ref.ReferenceQueue$Lock)
> 
>         at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:165)
> 
>         at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:216)
> 
> "Reference Handler" \#2 daemon prio=10 os\_prio=2 tid=0x000000001db90800 nid=0x924 in Object.wait() \[0x000000001e06f000\]
> 
>    java.lang.Thread.State: WAITING (on object monitor)
> 
>         at java.lang.Object.wait(Native Method)
> 
>         - waiting on <0x0000000770586c00> (a java.lang.ref.Reference$Lock)
> 
>         at java.lang.Object.wait(Object.java:502)
> 
>         at java.lang.ref.Reference.tryHandlePending(Reference.java:191)
> 
>         - locked <0x0000000770586c00> (a java.lang.ref.Reference$Lock)
> 
>         at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)
> 
> "VM Thread" os\_prio=2 tid=0x000000001bd89000 nid=0x4264 runnable
> 
> "GC task thread\#0 (ParallelGC)" os\_prio=0 tid=0x0000000002b78800 nid=0x35ac runnable
> 
> "GC task thread\#1 (ParallelGC)" os\_prio=0 tid=0x0000000002b7a000 nid=0x2eb8 runnable
> 
> "GC task thread\#2 (ParallelGC)" os\_prio=0 tid=0x0000000002b7b800 nid=0x20e0 runnable
> 
> "GC task thread\#3 (ParallelGC)" os\_prio=0 tid=0x0000000002b7d000 nid=0x4f3c runnable
> 
> "GC task thread\#4 (ParallelGC)" os\_prio=0 tid=0x0000000002b80800 nid=0x478c runnable
> 
> "GC task thread\#5 (ParallelGC)" os\_prio=0 tid=0x0000000002b81800 nid=0x9d4 runnable
> 
> "GC task thread\#6 (ParallelGC)" os\_prio=0 tid=0x0000000002b85000 nid=0x4c54 runnable
> 
> "GC task thread\#7 (ParallelGC)" os\_prio=0 tid=0x0000000002b86000 nid=0x4c2c runnable
> 
> "VM Periodic Task Thread" os\_prio=2 tid=0x000000001dc7d000 nid=0x4168 waiting on condition
> 
> JNI global references: 12
> 
> \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\# 死锁信息 \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#
> 
> Found one Java-level deadlock:
> 
> =============================
> 
> "Thread-1":
> 
>   waiting to lock monitor 0x000000001bd92228 (object 0x00000007708001a8, a java.lang.StringBuilder),
> 
>   which is held by "Thread-0"
> 
> "Thread-0":
> 
>   waiting to lock monitor 0x000000001bd936c8 (object 0x00000007708001f0, a java.lang.StringBuilder),
> 
>   which is held by "Thread-1"
> 
> Java stack information for the threads listed above:
> 
> ===================================================
> 
> "Thread-1":
> 
>         at chaper02.ThreadDeadLock$2.run(ThreadDeadLock.java:48)
> 
>         - waiting to lock <0x00000007708001a8> (a java.lang.StringBuilder)
> 
>         - locked <0x00000007708001f0> (a java.lang.StringBuilder)
> 
> "Thread-0":
> 
>         at chaper02.ThreadDeadLock$1.run(ThreadDeadLock.java:25)
> 
>         - waiting to lock <0x00000007708001f0> (a java.lang.StringBuilder)
> 
>         - locked <0x00000007708001a8> (a java.lang.StringBuilder)
> 
> Found 1 deadlock.
> 
> \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\# 死锁信息 \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#

# 三 实战——演示 TIMED\_WAITING #

## 1 代码 ##

package chaper02;
    
    /**
    * @className: ThreadSleepTest
    * @description: 演示 TIMED_WAITING
    * @date: 2021/8/22
    */
    public class ThreadSleepTest {
        public static void main(String[] args) {
            System.out.println("hello - 1");
            try {
                Thread.sleep(1000 * 60 * 10);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("hello -2");
        }
    }

## 2 测试 ##

> F:\\svn\\19\_byzb\_back\\branches\\JVMDemo3>jstack 2648
> 
> 2021-08-22 15:53:22
> 
> Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.251-b08 mixed mode):
> 
> "Service Thread" \#11 daemon prio=9 os\_prio=0 tid=0x000000001dac3800 nid=0x4994 runnable \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "C1 CompilerThread3" \#10 daemon prio=9 os\_prio=2 tid=0x000000001da27000 nid=0xd20 waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "C2 CompilerThread2" \#9 daemon prio=9 os\_prio=2 tid=0x000000001da21000 nid=0x4564 waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "C2 CompilerThread1" \#8 daemon prio=9 os\_prio=2 tid=0x000000001da1e000 nid=0x4f24 waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "C2 CompilerThread0" \#7 daemon prio=9 os\_prio=2 tid=0x000000001da0f800 nid=0x2bfc waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "Monitor Ctrl-Break" \#6 daemon prio=5 os\_prio=0 tid=0x000000001da0d000 nid=0x2d40 runnable \[0x000000001e24e000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
>         at java.net.SocketInputStream.socketRead0(Native Method)
> 
>         at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
> 
>         at java.net.SocketInputStream.read(SocketInputStream.java:171)
> 
>         at java.net.SocketInputStream.read(SocketInputStream.java:141)
> 
>         at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:284)
> 
>         at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:326)
> 
>         at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
> 
>         - locked <0x00000007706f2d58> (a java.io.InputStreamReader)
> 
>         at java.io.InputStreamReader.read(InputStreamReader.java:184)
> 
>         at java.io.BufferedReader.fill(BufferedReader.java:161)
> 
>         at java.io.BufferedReader.readLine(BufferedReader.java:324)
> 
>         - locked <0x00000007706f2d58> (a java.io.InputStreamReader)
> 
>         at java.io.BufferedReader.readLine(BufferedReader.java:389)
> 
>         at com.intellij.rt.execution.application.AppMainV2$1.run(AppMainV2.java:61)
> 
> "Attach Listener" \#5 daemon prio=5 os\_prio=2 tid=0x000000001d9d3800 nid=0x3b18 waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "Signal Dispatcher" \#4 daemon prio=9 os\_prio=2 tid=0x000000001d9d2800 nid=0x1ee8 runnable \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "Finalizer" \#3 daemon prio=8 os\_prio=1 tid=0x000000001d961000 nid=0x462c in Object.wait() \[0x000000001df3f000\]
> 
>    java.lang.Thread.State: WAITING (on object monitor)
> 
>         at java.lang.Object.wait(Native Method)
> 
>         - waiting on <0x0000000770588ee0> (a java.lang.ref.ReferenceQueue$Lock)
> 
>         at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144)
> 
>         - locked <0x0000000770588ee0> (a java.lang.ref.ReferenceQueue$Lock)
> 
>         at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:165)
> 
>         at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:216)
> 
> "Reference Handler" \#2 daemon prio=10 os\_prio=2 tid=0x000000001d960800 nid=0x40d0 in Object.wait() \[0x000000001de3f000\]
> 
>    java.lang.Thread.State: WAITING (on object monitor)
> 
>         at java.lang.Object.wait(Native Method)
> 
>         - waiting on <0x0000000770586c00> (a java.lang.ref.Reference$Lock)
> 
>         at java.lang.Object.wait(Object.java:502)
> 
>         at java.lang.ref.Reference.tryHandlePending(Reference.java:191)
> 
>         - locked <0x0000000770586c00> (a java.lang.ref.Reference$Lock)
> 
>         at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)
> 
> \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\# TIMED\_WAITING信息 \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#
> 
> "main" \#1 prio=5 os\_prio=0 tid=0x0000000000afe800 nid=0x10bc waiting on condition \[0x00000000027bf000\]
> 
>    java.lang.Thread.State: TIMED\_WAITING (sleeping)
> 
>         at java.lang.Thread.sleep(Native Method)
> 
>         at chaper02.ThreadSleepTest.main(ThreadSleepTest.java:12)
> 
> \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\# TIMED\_WAITING信息 \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#
> 
> "VM Thread" os\_prio=2 tid=0x000000001bb69800 nid=0x4934 runnable
> 
> "GC task thread\#0 (ParallelGC)" os\_prio=0 tid=0x0000000002958800 nid=0x1620 runnable
> 
> "GC task thread\#1 (ParallelGC)" os\_prio=0 tid=0x000000000295a000 nid=0xa64 runnable
> 
> "GC task thread\#2 (ParallelGC)" os\_prio=0 tid=0x000000000295b800 nid=0x356c runnable
> 
> "GC task thread\#3 (ParallelGC)" os\_prio=0 tid=0x000000000295d000 nid=0x2854 runnable
> 
> "GC task thread\#4 (ParallelGC)" os\_prio=0 tid=0x0000000002960800 nid=0x4d94 runnable
> 
> "GC task thread\#5 (ParallelGC)" os\_prio=0 tid=0x0000000002961800 nid=0x1798 runnable
> 
> "GC task thread\#6 (ParallelGC)" os\_prio=0 tid=0x0000000002965000 nid=0x1198 runnable
> 
> "GC task thread\#7 (ParallelGC)" os\_prio=0 tid=0x0000000002966000 nid=0x17d4 runnable
> 
> "VM Periodic Task Thread" os\_prio=2 tid=0x000000001dad5000 nid=0x944 waiting on condition

# 四 实战——演示线程同步 #

## 1 代码 ##

package chaper02;
    
    /**
    * @className: ThreadSyncTest
    * @description: 演示线程同步
    * @date: 2021/8/22
    */
    public class ThreadSyncTest {
        public static void main(String[] args) {
            Number number = new Number();
            Thread t1 = new Thread(number);
            Thread t2 = new Thread(number);
    
            t1.setName("线程1");
            t2.setName("线程2");
    
            t1.start();
            t2.start();
        }
    }
    
    class Number implements Runnable {
        private int number = 1;
    
        @Override
        public void run() {
            while (true) {
                synchronized (this) {
                    if (number <= 100) {
                        try {
                            Thread.sleep(500);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
    
                        System.out.println(Thread.currentThread().getName() + ":" + number);
                        number++;
                    } else {
                        break;
                    }
                }
            }
        }
    }

## 2 测试 ##

> F:\\svn\\19\_byzb\_back\\branches\\JVMDemo3>jstack 12504
> 
> 2021-08-22 16:04:16
> 
> Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.251-b08 mixed mode):
> 
> "DestroyJavaVM" \#14 prio=5 os\_prio=0 tid=0x0000000000b9e800 nid=0x419c waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\# 线程同步信息 \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#
> 
> "线程2" \#13 prio=5 os\_prio=0 tid=0x000000001dc04000 nid=0x4a10 waiting for monitor entry \[0x000000001eb6f000\]
> 
>    java.lang.Thread.State: BLOCKED (on object monitor)
> 
>         at chaper02.Number.run(ThreadSyncTest.java:29)
> 
>         - waiting to lock <0x0000000770802f08> (a chaper02.Number)
> 
>         at java.lang.Thread.run(Thread.java:748)
> 
> "线程1" \#12 prio=5 os\_prio=0 tid=0x000000001dc00000 nid=0x44dc waiting on condition \[0x000000001ea6f000\]
> 
>    java.lang.Thread.State: TIMED\_WAITING (sleeping)
> 
>         at java.lang.Thread.sleep(Native Method)
> 
>         at chaper02.Number.run(ThreadSyncTest.java:31)
> 
>         - locked <0x0000000770802f08> (a chaper02.Number)
> 
>         at java.lang.Thread.run(Thread.java:748)
> 
> \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\# 线程同步信息 \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#
> 
> "Service Thread" \#11 daemon prio=9 os\_prio=0 tid=0x000000001dbfb800 nid=0x4c74 runnable \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "C1 CompilerThread3" \#10 daemon prio=9 os\_prio=2 tid=0x000000001db8a800 nid=0x481c waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "C2 CompilerThread2" \#9 daemon prio=9 os\_prio=2 tid=0x000000001db63000 nid=0x4ea8 waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "C2 CompilerThread1" \#8 daemon prio=9 os\_prio=2 tid=0x000000001db4e000 nid=0xb4c waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "C2 CompilerThread0" \#7 daemon prio=9 os\_prio=2 tid=0x000000001db3f800 nid=0x4ae8 waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "Monitor Ctrl-Break" \#6 daemon prio=5 os\_prio=0 tid=0x000000001db3d000 nid=0x34d0 runnable \[0x000000001e36e000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
>         at java.net.SocketInputStream.socketRead0(Native Method)
> 
>         at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
> 
>         at java.net.SocketInputStream.read(SocketInputStream.java:171)
> 
>         at java.net.SocketInputStream.read(SocketInputStream.java:141)
> 
>         at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:284)
> 
>         at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:326)
> 
>         at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
> 
>         - locked <0x00000007706f2d58> (a java.io.InputStreamReader)
> 
>         at java.io.InputStreamReader.read(InputStreamReader.java:184)
> 
>         at java.io.BufferedReader.fill(BufferedReader.java:161)
> 
>         at java.io.BufferedReader.readLine(BufferedReader.java:324)
> 
>         - locked <0x00000007706f2d58> (a java.io.InputStreamReader)
> 
>         at java.io.BufferedReader.readLine(BufferedReader.java:389)
> 
>         at com.intellij.rt.execution.application.AppMainV2$1.run(AppMainV2.java:61)
> 
> "Attach Listener" \#5 daemon prio=5 os\_prio=2 tid=0x000000001db03800 nid=0x45b4 waiting on condition \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "Signal Dispatcher" \#4 daemon prio=9 os\_prio=2 tid=0x000000001db02800 nid=0x460c runnable \[0x0000000000000000\]
> 
>    java.lang.Thread.State: RUNNABLE
> 
> "Finalizer" \#3 daemon prio=8 os\_prio=1 tid=0x000000001da91000 nid=0x39fc in Object.wait() \[0x000000001e06f000\]
> 
>    java.lang.Thread.State: WAITING (on object monitor)
> 
>         at java.lang.Object.wait(Native Method)
> 
>         - waiting on <0x0000000770588ee0> (a java.lang.ref.ReferenceQueue$Lock)
> 
>         at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144)
> 
>         - locked <0x0000000770588ee0> (a java.lang.ref.ReferenceQueue$Lock)
> 
>         at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:165)
> 
>         at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:216)
> 
> "Reference Handler" \#2 daemon prio=10 os\_prio=2 tid=0x000000001da90800 nid=0x118c in Object.wait() \[0x000000001df6f000\]
> 
>    java.lang.Thread.State: WAITING (on object monitor)
> 
>         at java.lang.Object.wait(Native Method)
> 
>         - waiting on <0x0000000770586c00> (a java.lang.ref.Reference$Lock)
> 
>         at java.lang.Object.wait(Object.java:502)
> 
>         at java.lang.ref.Reference.tryHandlePending(Reference.java:191)
> 
>         - locked <0x0000000770586c00> (a java.lang.ref.Reference$Lock)
> 
>         at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)
> 
> "VM Thread" os\_prio=2 tid=0x000000001bc79000 nid=0x814 runnable
> 
> "GC task thread\#0 (ParallelGC)" os\_prio=0 tid=0x0000000002a68800 nid=0x3798 runnable
> 
> "GC task thread\#1 (ParallelGC)" os\_prio=0 tid=0x0000000002a6a000 nid=0x2678 runnable
> 
> "GC task thread\#2 (ParallelGC)" os\_prio=0 tid=0x0000000002a6b800 nid=0x2468 runnable
> 
> "GC task thread\#3 (ParallelGC)" os\_prio=0 tid=0x0000000002a6d000 nid=0x3198 runnable
> 
> "GC task thread\#4 (ParallelGC)" os\_prio=0 tid=0x0000000002a70800 nid=0xa6c runnable
> 
> "GC task thread\#5 (ParallelGC)" os\_prio=0 tid=0x0000000002a71800 nid=0x3ad0 runnable
> 
> "GC task thread\#6 (ParallelGC)" os\_prio=0 tid=0x0000000002a75000 nid=0x47c4 runnable
> 
> "GC task thread\#7 (ParallelGC)" os\_prio=0 tid=0x0000000002a76000 nid=0x4ce0 runnable
> 
> "VM Periodic Task Thread" os\_prio=2 tid=0x000000001dbff000 nid=0x35e0 waiting on condition
> 
> JNI global references: 12

# 五 实战——追踪当前进程中的所有线程 #

## 1 代码 ##

package chaper02;
    
    import java.util.Map;
    import java.util.Set;
    
    /**
    * @className: AllStackTrace
    * @description: // 追踪当前进程中的所有线程
    * @date: 2021/8/22
    */
    public class AllStackTrace {
        public static void main(String[] args) {
            Map<Thread, StackTraceElement[]> allStackTraces = Thread.getAllStackTraces();
            Set<Map.Entry<Thread, StackTraceElement[]>> entries = allStackTraces.entrySet(); // 追踪当前进程中的所有线程
            for (Map.Entry<Thread, StackTraceElement[]> en : entries) {
                Thread t = en.getKey();
                StackTraceElement[] v = en.getValue();
                System.out.println("[Thread name is :" + t.getName() + "]");
                for (StackTraceElement s : v) {
                    System.out.println("\t" + s.toString());
                }
            }
        }
    }

## 2 测试 ##

> \[Thread name is :Attach Listener\]
> 
> \[Thread name is :Monitor Ctrl-Break\]
> 
>     java.net.URI$Parser.parse(URI.java:3046)
> 
>     java.net.URI.<init>(URI.java:588)
> 
>     java.net.SocksSocketImpl.connect(SocksSocketImpl.java:375)
> 
>     java.net.Socket.connect(Socket.java:606)
> 
>     java.net.Socket.connect(Socket.java:555)
> 
>     java.net.Socket.<init>(Socket.java:451)
> 
>     java.net.Socket.<init>(Socket.java:228)
> 
>     com.intellij.rt.execution.application.AppMainV2$1.run(AppMainV2.java:56)
> 
> \[Thread name is :Signal Dispatcher\]
> 
> \[Thread name is :Finalizer\]
> 
>     java.lang.Object.wait(Native Method)
> 
>     java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144)
> 
>     java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:165)
> 
>     java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:216)
> 
> \[Thread name is :Reference Handler\]
> 
>     java.lang.Object.wait(Native Method)
> 
>     java.lang.Object.wait(Object.java:502)
> 
>     java.lang.ref.Reference.tryHandlePending(Reference.java:191)
> 
>     java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)
> 
> \[Thread name is :main\]
> 
>     java.lang.Thread.dumpThreads(Native Method)
> 
>     java.lang.Thread.getAllStackTraces(Thread.java:1610)
> 
>     chaper02.AllStackTrace.main(AllStackTrace.java:8)
> 
> Process finished with exit code 0

[https_docs.oracle.com_en_java_javase_11_tools_jstack.html]: https://docs.oracle.com/en/java/javase/11/tools/jstack.html