/*
* Copyright (C) 2009 The doctor Authors
* https://github.com/doctorwho1986
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
*
* @author doctor
*
* @date 2014年8月23日 下午8:46:37
*/
public class DeadLock {
/**
* 1、linux 命令 kill -3 pid 对于线程状态观察,eclipse console 会输出
* 2、java 命令 jstack pid 观察线程状态。
* @param args
*/
public static void main(String[] args) {
//得到jvm线程pid，用命令观察线程死锁信息
System.out.println(ManagementFactory.getRuntimeMXBean().getName());
DeadLockAB deadLockAB = new DeadLockAB();
new Thread(new Dead1(deadLockAB)).start();
new Thread(new Dead2(deadLockAB)).start();
}
}
class DeadLockAB{
private Object a = new Object();
private Object b = new Object();
public void callAB() {
synchronized (a) {
System.out.println(Thread.currentThread().getName() + " get a");
synchronized (b) {
System.out.println(Thread.currentThread().getName() + " get b");
}
System.out.println(Thread.currentThread().getName() + " release b");
}
System.out.println(Thread.currentThread().getName() + " release a");
}
public void callBA() {
synchronized (b) {
System.out.println(Thread.currentThread().getName() + "get b");
synchronized (a) {
System.out.println(Thread.currentThread().getName() + " get a");
}
System.out.println(Thread.currentThread().getName() + " release a");
}
System.out.println(Thread.currentThread().getName() + " release b");
}
}
class Dead1 implements Runnable{
private DeadLockAB deadLockAB;
public Dead1(DeadLockAB deadLockAB) {
this.deadLockAB = deadLockAB;
}
@Override
public void run() {
try {
while(true){
deadLockAB.callAB();
TimeUnit.SECONDS.sleep((int)Math.random()*10L);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
class Dead2 implements Runnable{
private DeadLockAB deadLockAB;
public Dead2(DeadLockAB deadLockAB) {
this.deadLockAB = deadLockAB;
}
@Override
public void run() {
try {
while(true){
deadLockAB.callBA();
TimeUnit.SECONDS.sleep((int)Math.random()*10L);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
当eclipse console 不再出现信息即死锁状态时候，用注释中的两条命令观察信息。
贴出信息;
[doctor@localhost ~]$ jstack 18773 2014-08-23 21:33:17 Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.11-b03 mixed mode): "Attach Listener" #12 daemon prio=9 os_prio=0 tid=0x00007fd268001000 nid=0x4982 waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE "DestroyJavaVM" #11 prio=5 os_prio=0 tid=0x00007fd2a4009800 nid=0x495b waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE "Thread-1" #10 prio=5 os_prio=0 tid=0x00007fd2a40fc000 nid=0x496b waiting for monitor entry [0x00007fd290aea000] java.lang.Thread.State: BLOCKED (on object monitor) at com.github.jdk.concurrent.DeadLockAB.callBA(DeadLock.java:49) - waiting to lock <0x00000000d810a108> (a java.lang.Object) - locked <0x00000000d810a118> (a java.lang.Object) at com.github.jdk.concurrent.Dead2.run(DeadLock.java:91) at java.lang.Thread.run(Thread.java:745) "Thread-0" #9 prio=5 os_prio=0 tid=0x00007fd2a40fa000 nid=0x496a waiting for monitor entry [0x00007fd290beb000] java.lang.Thread.State: BLOCKED (on object monitor) at com.github.jdk.concurrent.DeadLockAB.callAB(DeadLock.java:38) - waiting to lock <0x00000000d810a118> (a java.lang.Object) - locked <0x00000000d810a108> (a java.lang.Object) at com.github.jdk.concurrent.Dead1.run(DeadLock.java:68) at java.lang.Thread.run(Thread.java:745) "Service Thread" #8 daemon prio=9 os_prio=0 tid=0x00007fd2a40d7000 nid=0x4968 runnable [0x0000000000000000] java.lang.Thread.State: RUNNABLE "C1 CompilerThread2" #7 daemon prio=9 os_prio=0 tid=0x00007fd2a40b1800 nid=0x4967 waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE "C2 CompilerThread1" #6 daemon prio=9 os_prio=0 tid=0x00007fd2a40b0000 nid=0x4966 waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE "C2 CompilerThread0" #5 daemon prio=9 os_prio=0 tid=0x00007fd2a40ad000 nid=0x4965 waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE "Signal Dispatcher" #4 daemon prio=9 os_prio=0 tid=0x00007fd2a40ab000 nid=0x4964 runnable [0x0000000000000000] java.lang.Thread.State: RUNNABLE "Finalizer" #3 daemon prio=8 os_prio=0 tid=0x00007fd2a407c000 nid=0x4963 in Object.wait() [0x00007fd2a837d000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <0x00000000d81809b0> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:142) - locked <0x00000000d81809b0> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:158) at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:209) "Reference Handler" #2 daemon prio=10 os_prio=0 tid=0x00007fd2a4078000 nid=0x4962 in Object.wait() [0x00007fd2a847e000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <0x00000000d81889d8> (a java.lang.ref.Reference$Lock) at java.lang.Object.wait(Object.java:502) at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:157) - locked <0x00000000d81889d8> (a java.lang.ref.Reference$Lock) "VM Thread" os_prio=0 tid=0x00007fd2a4072800 nid=0x4961 runnable "GC task thread#0 (ParallelGC)" os_prio=0 tid=0x00007fd2a401f000 nid=0x495d runnable "GC task thread#1 (ParallelGC)" os_prio=0 tid=0x00007fd2a4020800 nid=0x495e runnable "GC task thread#2 (ParallelGC)" os_prio=0 tid=0x00007fd2a4022800 nid=0x495f runnable "GC task thread#3 (ParallelGC)" os_prio=0 tid=0x00007fd2a4024000 nid=0x4960 runnable "VM Periodic Task Thread" os_prio=0 tid=0x00007fd2a40e1800 nid=0x4969 waiting on condition JNI global references: 18 Found one Java-level deadlock: ============================= "Thread-1": waiting to lock monitor 0x00007fd274006168 (object 0x00000000d810a108, a java.lang.Object), which is held by "Thread-0" "Thread-0": waiting to lock monitor 0x00007fd274003828 (object 0x00000000d810a118, a java.lang.Object), which is held by "Thread-1" Java stack information for the threads listed above: =================================================== "Thread-1": at com.github.jdk.concurrent.DeadLockAB.callBA(DeadLock.java:49) - waiting to lock <0x00000000d810a108> (a java.lang.Object) - locked <0x00000000d810a118> (a java.lang.Object) at com.github.jdk.concurrent.Dead2.run(DeadLock.java:91) at java.lang.Thread.run(Thread.java:745) "Thread-0": at com.github.jdk.concurrent.DeadLockAB.callAB(DeadLock.java:38) - waiting to lock <0x00000000d810a118> (a java.lang.Object) - locked <0x00000000d810a108> (a java.lang.Object) at com.github.jdk.concurrent.Dead1.run(DeadLock.java:68) at java.lang.Thread.run(Thread.java:745) Found 1 deadlock. [doctor@localhost ~]$