import java.util.concurrent.TimeUnit;

import java.util.concurrent.atomic.AtomicInteger;

import java.util.concurrent.atomic.AtomicStampedReference;

public class ABA {

private static AtomicInteger atomicInt = new AtomicInteger(100);

//AtomicStampedReference来解决ABA问题

private static AtomicStampedReference<Integer> atomicStampedRef =

new AtomicStampedReference<Integer>(100, 0);

public static void main(String[] args) throws InterruptedException {

Thread intT1 = new Thread(new Runnable() {

@Override

public void run() {

atomicInt.compareAndSet(100, 101);

atomicInt.compareAndSet(101, 100);

}

});

Thread intT2 = new Thread(new Runnable() {

@Override

public void run() {

try {

TimeUnit.SECONDS.sleep(1);

} catch (InterruptedException e) {

e.printStackTrace();

}

boolean c3 = atomicInt.compareAndSet(100, 101);

System.out.println(c3); //true

}

});

intT1.start();

intT2.start();

intT1.join();

intT2.join();

Thread refT1 = new Thread(new Runnable() {

@Override

public void run() {

try {

TimeUnit.SECONDS.sleep(1);

} catch (InterruptedException e) {

e.printStackTrace();

}

atomicStampedRef.compareAndSet(100, 101,

atomicStampedRef.getStamp(), atomicStampedRef.getStamp()+1);

atomicStampedRef.compareAndSet(101, 100,

atomicStampedRef.getStamp(), atomicStampedRef.getStamp()+1);

}

});

Thread refT2 = new Thread(new Runnable() {

@Override

public void run() {

int stamp = atomicStampedRef.getStamp();

System.out.println("before sleep : stamp = " + stamp); // stamp = 0

try {

TimeUnit.SECONDS.sleep(2);

} catch (InterruptedException e) {

e.printStackTrace();

}

System.out.println("after sleep : stamp = " + atomicStampedRef.getStamp());//stamp = 1

boolean c3 = atomicStampedRef.compareAndSet(100, 101, stamp, stamp+1);

System.out.println(c3); //false

}

});

refT1.start();

refT2.start();

}

}