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Copy pathDeadlock.java
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104 lines (80 loc) · 2.55 KB
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package thread;
/**
* Created by yahier on 10/30/18.
* 测试 死锁
*/
public class Deadlock {
private String objID;
private Deadlock(String id) {
objID = id;
}
public static void main(String[] args) {
final Deadlock obj1 = new Deadlock("obj1");
final Deadlock obj2 = new Deadlock("obj2");
Thread threadA = new Thread(() -> {
obj1.checkOther(obj2);
}, "threadA");
threadA.start();
try {
Thread.sleep(200);
} catch (InterruptedException x) {
//pass
}
Thread threadB = new Thread(() -> {
obj2.checkOther(obj1);
}, "threadB");
threadB.start();
try {
Thread.sleep(5000);
} catch (InterruptedException x) {
//pass
}
threadPrint("finished sleeping");
threadPrint("about to interrupt() threadA");
threadA.interrupt();
try {
Thread.sleep(1000);
} catch (InterruptedException x) {
}
threadPrint("about to interrupt() threadB");
threadB.interrupt();
try {
Thread.sleep(1000);
} catch (InterruptedException x) {
}
threadPrint("did that break the deadlock?");
}
/**
* 同时进入了此方法，因为 锁的对象不同
*/
private synchronized void checkOther(Deadlock other) {
print("entering checkOther()");
try {
Thread.sleep(2000);
} catch (InterruptedException x) {
}
print("in checkOther() - about to " + "invoke 'other.action()'");
//调用other对象的action方法，由于该方法是同步方法，因此会试图获取other对象的对象锁
other.action();
print("leaving checkOther()");
}
/**
* 都不能进入到此方法。
* 在执行到上面的other.action() 时，由于两个线程都在试图获取对方的锁，但对方都没有释放自己的锁，因而便产生了死锁，在主线程中试图中断两个线程，但都无果
*/
private synchronized void action() {
print("entering action()");
try {
Thread.sleep(500);
} catch (InterruptedException x) {
}
print("leaving action()");
}
public void print(String msg) {
threadPrint("objID=" + objID + " - " + msg);
}
private static void threadPrint(String msg) {
String threadName = Thread.currentThread().getName();
System.out.println(threadName + ": " + msg);
}
}