jstack如何分析ScheduledExecutorService没有关闭

Question

背景：使用context.close之后，进程没有结束。后来发现，自己在代码中写了一个线程池，并没有让线程池关闭，因此导致context close之后，进程还在。

刚好近期了解了 jstack的使用，可以查看进程中还有哪些线程。比如文章https://blog.csdn.net/liwenxi... 中介绍了jstack分析cpu占用100%，以及jstack分析死锁问题。但是这些没有提到对于线程池的方式如何查找分析原因。

假设现在我并不知道是因为有这个线程池没有关闭的原因，那么我使用jstack，怎么样可以找到context close之后进程没有结束的原因呢？

使用

ConfigurableApplicationContext context = SpringApplication.run(Application.class, args);
context.close();

关闭之后，应用的进程并没有结束。

ScheduledExecutorService executor = new ScheduledThreadPoolExecutor(1, new BasicThreadFactory.Builder().namingPattern("Thrift-Pool-metrics-tracker-%d").daemon(false).build());
//定时打点
executor.scheduleAtFixedRate(()-> {
    try {
        System.out.println(System.currentTimeMillis()+"定时打点的任务");
    } catch (Throwable t){

    }
}, 0,1, TimeUnit.SECONDS);

使用jstack分析，看到有以下线程并没有关闭：

$ jstack 82211
2020-05-23 22:15:05
Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.181-b13 mixed mode):

"DestroyJavaVM" #66 prio=5 os_prio=31 tid=0x00007f81f1b80000 nid=0x2703 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Thrift-Pool-metrics-tracker-1" #61 prio=5 os_prio=31 tid=0x00007f81f2a9f000 nid=0xa81f waiting on condition [0x000070000e8a2000]
   java.lang.Thread.State: TIMED_WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00000007967d1238> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
    at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093)
    at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
    at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

"Abandoned connection cleanup thread" #27 daemon prio=5 os_prio=31 tid=0x00007f81f1381000 nid=0xa407 in Object.wait() [0x000070000efb7000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x0000000740dfb730> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144)
    - locked <0x0000000740dfb730> (a java.lang.ref.ReferenceQueue$Lock)
    at com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:64)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

"RMI Scheduler(0)" #15 daemon prio=5 os_prio=31 tid=0x00007f81f1262800 nid=0x5503 waiting on condition [0x000070000ebab000]
   java.lang.Thread.State: TIMED_WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x0000000740014018> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
    at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093)
    at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
    at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

"Attach Listener" #13 daemon prio=9 os_prio=31 tid=0x00007f81f2270800 nid=0x4003 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"RMI TCP Accept-0" #11 daemon prio=5 os_prio=31 tid=0x00007f81f2867800 nid=0x4403 runnable [0x000070000e69c000]
   java.lang.Thread.State: RUNNABLE
    at java.net.PlainSocketImpl.socketAccept(Native Method)
    at java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:409)
    at java.net.ServerSocket.implAccept(ServerSocket.java:545)
    at java.net.ServerSocket.accept(ServerSocket.java:513)
    at sun.management.jmxremote.LocalRMIServerSocketFactory$1.accept(LocalRMIServerSocketFactory.java:52)
    at sun.rmi.transport.tcp.TCPTransport$AcceptLoop.executeAcceptLoop(TCPTransport.java:405)
    at sun.rmi.transport.tcp.TCPTransport$AcceptLoop.run(TCPTransport.java:377)
    at java.lang.Thread.run(Thread.java:748)

"Service Thread" #9 daemon prio=9 os_prio=31 tid=0x00007f81f2819000 nid=0x3a03 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C1 CompilerThread2" #8 daemon prio=9 os_prio=31 tid=0x00007f81f2818000 nid=0x4603 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread1" #7 daemon prio=9 os_prio=31 tid=0x00007f81f20a6800 nid=0x3803 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread0" #6 daemon prio=9 os_prio=31 tid=0x00007f81f204b800 nid=0x4803 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Monitor Ctrl-Break" #5 daemon prio=5 os_prio=31 tid=0x00007f81f2049800 nid=0x3603 runnable [0x000070000e18d000]
   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 <0x0000000740080360> (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 <0x0000000740080360> (a java.io.InputStreamReader)
    at java.io.BufferedReader.readLine(BufferedReader.java:389)
    at com.intellij.rt.execution.application.AppMainV2$1.run(AppMainV2.java:61)

"Signal Dispatcher" #4 daemon prio=9 os_prio=31 tid=0x00007f81f107c000 nid=0x3403 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Finalizer" #3 daemon prio=8 os_prio=31 tid=0x00007f81f1007800 nid=0x2e03 in Object.wait() [0x000070000df87000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000007400812e8> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144)
    - locked <0x00000007400812e8> (a java.lang.ref.ReferenceQueue$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=31 tid=0x00007f81f1811000 nid=0x5103 in Object.wait() [0x000070000de84000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000007400932d0> (a java.lang.ref.Reference$Lock)
    at java.lang.Object.wait(Object.java:502)
    at java.lang.ref.Reference.tryHandlePending(Reference.java:191)
    - locked <0x00000007400932d0> (a java.lang.ref.Reference$Lock)
    at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)

"VM Thread" os_prio=31 tid=0x00007f81f180c000 nid=0x2c03 runnable

"GC task thread#0 (ParallelGC)" os_prio=31 tid=0x00007f81f1809800 nid=0x1d07 runnable

"GC task thread#1 (ParallelGC)" os_prio=31 tid=0x00007f81f1011000 nid=0x1e03 runnable

"GC task thread#2 (ParallelGC)" os_prio=31 tid=0x00007f81f1012000 nid=0x2b03 runnable

"GC task thread#3 (ParallelGC)" os_prio=31 tid=0x00007f81f1012800 nid=0x5303 runnable

"VM Periodic Task Thread" os_prio=31 tid=0x00007f81f19e5800 nid=0x4303 waiting on condition

JNI global references: 1317

Answer 1

jstack 定位线程状况，重点关注：WAITING，TIMED_WAITING， BLOCKED这几种状态的线程。