package concurrency;import java.util.concurrent.atomic.AtomicReference;public class TestConcurrency {    private static volatile Integer         num1 = 0;    private static Integer         num2 = 0;    private static AtomicReference<Integer> ar   = new AtomicReference<Integer>(num1);    public static void dfasd111() throws InterruptedException {        for (int i = 0; i < 1000; i++) {            new Thread(new Runnable() {                public void run() {                    for (int i = 0; i < 10000; i++)                        while (true) {                            Integer temp = ar.get();                            if (ar.compareAndSet(temp, temp + 1)) break;                        }                }            }).start();        }        Thread.sleep(10000);        System.out.println(ar.get()); // 10000000    }    public static void dfasd1112() throws InterruptedException {        for (int i = 0; i < 1000; i++) {            new Thread(new Runnable() {                public void run() {                    for (int i = 0; i < 10000; i++) {                        num1 = num1++;                    }                }            }).start();        }        Thread.sleep(10000);        System.out.println(num1); // something like 238981    }    public static void funnum2() throws InterruptedException {        for (int i = 0; i < 1000; i++) {            new Thread(new Runnable() {                public void run() {                    for (int i = 0; i < 10000; i++) {                        num2 = num2++;                    }                }            }).start();        }        Thread.sleep(10000);        System.out.println(num2); // something like 238981    }        public static void main(String[] args) {        try {           // dfasd111();            //dfasd1112();            funnum2();        } catch (InterruptedException e) {                        // TODO Auto-generated catch block e.printStackTrace();                    }    }}