对SIGQUIT的实验 & Java dump

写了一个Java程序，sleep 20秒。

package com.company;

public class Main {

    public static void main(String[] args) {
        try {
            Thread.sleep(20000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        System.out.println("Done");

    }
}

运行之后，用kill -3 pid来实验，得到下面的结果：

$ java -jar leetcode.jar 
2016-12-15 14:59:22
Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.101-b13 mixed mode):

"Service Thread" #8 daemon prio=9 os_prio=31 tid=0x00007fa1fc04d000 nid=0x4903 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C1 CompilerThread2" #7 daemon prio=9 os_prio=31 tid=0x00007fa1fa866800 nid=0x4703 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread1" #6 daemon prio=9 os_prio=31 tid=0x00007fa1fa83c800 nid=0x4503 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread0" #5 daemon prio=9 os_prio=31 tid=0x00007fa1fc041800 nid=0x4303 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Signal Dispatcher" #4 daemon prio=9 os_prio=31 tid=0x00007fa1fc057800 nid=0x360f waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Finalizer" #3 daemon prio=8 os_prio=31 tid=0x00007fa1fa85c800 nid=0x3003 in Object.wait() [0x000070000092e000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x0000000795588ee0> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
    - locked <0x0000000795588ee0> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:164)
    at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:209)

"Reference Handler" #2 daemon prio=10 os_prio=31 tid=0x00007fa1fa859800 nid=0x2e03 in Object.wait() [0x000070000082b000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x0000000795586b50> (a java.lang.ref.Reference$Lock)
    at java.lang.Object.wait(Object.java:502)
    at java.lang.ref.Reference.tryHandlePending(Reference.java:191)
    - locked <0x0000000795586b50> (a java.lang.ref.Reference$Lock)
    at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)

"main" #1 prio=5 os_prio=31 tid=0x00007fa1fb002800 nid=0x1703 waiting on condition [0x0000700000219000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
    at java.lang.Thread.sleep(Native Method)
    at com.company.Main.main(Main.java:10)

"VM Thread" os_prio=31 tid=0x00007fa1fa855000 nid=0x2c03 runnable 

"GC task thread#0 (ParallelGC)" os_prio=31 tid=0x00007fa1fc003800 nid=0x2403 runnable 

"GC task thread#1 (ParallelGC)" os_prio=31 tid=0x00007fa1fc004000 nid=0x2603 runnable 

"GC task thread#2 (ParallelGC)" os_prio=31 tid=0x00007fa1fc005000 nid=0x2803 runnable 

"GC task thread#3 (ParallelGC)" os_prio=31 tid=0x00007fa1fc005800 nid=0x2a03 runnable 

"VM Periodic Task Thread" os_prio=31 tid=0x00007fa1fa879800 nid=0x4b03 waiting on condition 

JNI global references: 6

Heap
 PSYoungGen      total 38400K, used 1996K [0x0000000795580000, 0x0000000798000000, 0x00000007c0000000)
  eden space 33280K, 6% used [0x0000000795580000,0x00000007957733b8,0x0000000797600000)
  from space 5120K, 0% used [0x0000000797b00000,0x0000000797b00000,0x0000000798000000)
  to   space 5120K, 0% used [0x0000000797600000,0x0000000797600000,0x0000000797b00000)
 ParOldGen       total 87552K, used 0K [0x0000000740000000, 0x0000000745580000, 0x0000000795580000)
  object space 87552K, 0% used [0x0000000740000000,0x0000000740000000,0x0000000745580000)
 Metaspace       used 2716K, capacity 4486K, committed 4864K, reserved 1056768K
  class space    used 293K, capacity 386K, committed 512K, reserved 1048576K

Done

注意，sleep的时间，还是会正常走完的。

可以看到里面飘黄的那一行，是在sleeping的。