死锁范例:
package com.array7.concurrent;
public class DeadLockTest {
private static Object res1 = new Object();
private static Object res2 = new Object();
public static void main(String[] args) {
for (int i = 0; i < 5; i++) {
new Thread(new MyRun1()).start();
new Thread(new MyRun2()).start();
}
}
public static class MyRun1 implements Runnable {
@Override
public void run() {
synchronized (res1) {
System.out.println("MyRun1 res1......");
synchronized (res2) {
System.out.println("MyRun1 res2......");
}
}
}
}
public static class MyRun2 implements Runnable {
@Override
public void run() {
synchronized (res2) {
System.out.println("MyRun2 res1......");
synchronized (res1) {
System.out.println("MyRun2 res2......");
}
}
}
}
}
jstack
2015-10-20 11:58:49
Full thread dump Java HotSpot(TM) 64-Bit Server VM (24.51-b03 mixed mode):
"DestroyJavaVM" prio=6 tid=0x000000000241e000 nid=0x16a8 waiting on condition [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
Locked ownable synchronizers:
- None
"Thread-9" prio=6 tid=0x000000000c3c9000 nid=0x2760 waiting for monitor entry [0x000000000d7df000]
java.lang.Thread.State: BLOCKED (on object monitor)
at com.array7.concurrent.DeadLockTest$MyRun2.run(DeadLockTest.java:27)
- waiting to lock <0x00000007d5b98738> (a java.lang.Object)
at java.lang.Thread.run(Thread.java:744)
Locked ownable synchronizers:
- None
"Thread-8" prio=6 tid=0x000000000c3c8800 nid=0x279c waiting for monitor entry [0x000000000d5cf000]
java.lang.Thread.State: BLOCKED (on object monitor)
at com.array7.concurrent.DeadLockTest$MyRun1.run(DeadLockTest.java:16)
- waiting to lock <0x00000007d5b98728> (a java.lang.Object)
at java.lang.Thread.run(Thread.java:744)
Locked ownable synchronizers:
- None
"Thread-7" prio=6 tid=0x000000000c3c6800 nid=0x274c waiting for monitor entry [0x000000000d38f000]
java.lang.Thread.State: BLOCKED (on object monitor)
at com.array7.concurrent.DeadLockTest$MyRun2.run(DeadLockTest.java:27)
- waiting to lock <0x00000007d5b98738> (a java.lang.Object)
at java.lang.Thread.run(Thread.java:744)
Locked ownable synchronizers:
- None
"Thread-6" prio=6 tid=0x000000000c3c3800 nid=0x276c waiting for monitor entry [0x000000000d4be000]
java.lang.Thread.State: BLOCKED (on object monitor)
at com.array7.concurrent.DeadLockTest$MyRun1.run(DeadLockTest.java:16)
- waiting to lock <0x00000007d5b98728> (a java.lang.Object)
at java.lang.Thread.run(Thread.java:744)
Locked ownable synchronizers:
- None
"Thread-5" prio=6 tid=0x000000000c3c3000 nid=0x2784 waiting for monitor entry [0x000000000d23f000]
java.lang.Thread.State: BLOCKED (on object monitor)
at com.array7.concurrent.DeadLockTest$MyRun2.run(DeadLockTest.java:27)
- waiting to lock <0x00000007d5b98738> (a java.lang.Object)
at java.lang.Thread.run(Thread.java:744)
Locked ownable synchronizers:
- None
"Thread-4" prio=6 tid=0x000000000c3b8800 nid=0x2798 waiting for monitor entry [0x000000000d0ff000]
java.lang.Thread.State: BLOCKED (on object monitor)
at com.array7.concurrent.DeadLockTest$MyRun1.run(DeadLockTest.java:16)
- waiting to lock <0x00000007d5b98728> (a java.lang.Object)
at java.lang.Thread.run(Thread.java:744)
Locked ownable synchronizers:
- None
"Thread-3" prio=6 tid=0x000000000c3b8000 nid=0x2794 waiting for monitor entry [0x000000000cf2f000]
java.lang.Thread.State: BLOCKED (on object monitor)
at com.array7.concurrent.DeadLockTest$MyRun2.run(DeadLockTest.java:29)
- waiting to lock <0x00000007d5b98728> (a java.lang.Object)
- locked <0x00000007d5b98738> (a java.lang.Object)
at java.lang.Thread.run(Thread.java:744)
Locked ownable synchronizers:
- None
"Thread-2" prio=6 tid=0x000000000c3b7000 nid=0x282c waiting for monitor entry [0x000000000ce2f000]
java.lang.Thread.State: BLOCKED (on object monitor)
at com.array7.concurrent.DeadLockTest$MyRun1.run(DeadLockTest.java:18)
- waiting to lock <0x00000007d5b98738> (a java.lang.Object)
- locked <0x00000007d5b98728> (a java.lang.Object)
at java.lang.Thread.run(Thread.java:744)
Locked ownable synchronizers:
- None
"Service Thread" daemon prio=6 tid=0x000000000c3a3000 nid=0x2550 runnable [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
Locked ownable synchronizers:
- None
"C2 CompilerThread1" daemon prio=10 tid=0x000000000c3a1000 nid=0x2958 waiting on condition [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
Locked ownable synchronizers:
- None
"C2 CompilerThread0" daemon prio=10 tid=0x000000000aeb9000 nid=0x2954 waiting on condition [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
Locked ownable synchronizers:
- None
"Attach Listener" daemon prio=10 tid=0x000000000aeb8000 nid=0x2940 waiting on condition [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
Locked ownable synchronizers:
- None
"Signal Dispatcher" daemon prio=10 tid=0x000000000aeb1000 nid=0x2928 runnable [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
Locked ownable synchronizers:
- None
"Finalizer" daemon prio=8 tid=0x000000000ae46800 nid=0x21ec in Object.wait() [0x000000000c00f000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <0x00000007d5b05568> (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:135)
- locked <0x00000007d5b05568> (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:151)
at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:189)
Locked ownable synchronizers:
- None
"Reference Handler" daemon prio=10 tid=0x000000000ae3d800 nid=0x2970 in Object.wait() [0x000000000605f000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <0x00000007d5b050f0> (a java.lang.ref.Reference$Lock)
at java.lang.Object.wait(Object.java:503)
at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:133)
- locked <0x00000007d5b050f0> (a java.lang.ref.Reference$Lock)
Locked ownable synchronizers:
- None
"VM Thread" prio=10 tid=0x000000000ae38000 nid=0x295c runnable
"GC task thread#0 (ParallelGC)" prio=6 tid=0x000000000246d000 nid=0x267c runnable
"GC task thread#1 (ParallelGC)" prio=6 tid=0x000000000246f000 nid=0x2120 runnable
"GC task thread#2 (ParallelGC)" prio=6 tid=0x0000000002470800 nid=0x25d0 runnable
"GC task thread#3 (ParallelGC)" prio=6 tid=0x0000000002472000 nid=0x16c8 runnable
"VM Periodic Task Thread" prio=10 tid=0x000000000c3b4000 nid=0x28d4 waiting on condition
JNI global references: 105
Found one Java-level deadlock:
=============================
"Thread-9":
waiting to lock monitor 0x000000000c3be7b8 (object 0x00000007d5b98738, a java.lang.Object),
which is held by "Thread-3"
"Thread-3":
waiting to lock monitor 0x000000000ae463a8 (object 0x00000007d5b98728, a java.lang.Object),
which is held by "Thread-2"
"Thread-2":
waiting to lock monitor 0x000000000c3be7b8 (object 0x00000007d5b98738, a java.lang.Object),
which is held by "Thread-3"
Java stack information for the threads listed above:
===================================================
"Thread-9":
at com.array7.concurrent.DeadLockTest$MyRun2.run(DeadLockTest.java:27)
- waiting to lock <0x00000007d5b98738> (a java.lang.Object)
at java.lang.Thread.run(Thread.java:744)
"Thread-3":
at com.array7.concurrent.DeadLockTest$MyRun2.run(DeadLockTest.java:29)
- waiting to lock <0x00000007d5b98728> (a java.lang.Object)
- locked <0x00000007d5b98738> (a java.lang.Object)
at java.lang.Thread.run(Thread.java:744)
"Thread-2":
at com.array7.concurrent.DeadLockTest$MyRun1.run(DeadLockTest.java:18)
- waiting to lock <0x00000007d5b98738> (a java.lang.Object)
- locked <0x00000007d5b98728> (a java.lang.Object)
at java.lang.Thread.run(Thread.java:744)
Found 1 deadlock.