示例

public class AtomicDemo {    static int num1 = 0;    static AtomicInteger num2 = new AtomicInteger(0);    static class Thread1 extends Thread {        @Override        public void run() {            try {                sleep(100);            } catch (InterruptedException e) {                e.printStackTrace();            }            num1++;        }    }    static class Thread2 extends Thread {        @Override        public void run() {            try {                sleep(100);            } catch (InterruptedException e) {                e.printStackTrace();            }            num2.incrementAndGet();        }    }    public static void main(String[] args) throws InterruptedException {        for (int i = 0; i < 1000; i++) {            new Thread1().start();            new Thread2().start();        }        Thread.sleep(2000);        System.out.println("num1=" + num1);        System.out.println("num2=" + num2.get());    }}

运行结果如下：

在多线程无锁的情况下，num1总是小于等于1000，而num2因为原子性的方法总是等于1000。