多线程8---volatile2---多线程间变量的可见性不具备原子性---AtomicInteger

1.

public class VolatileNoAtomic extends Thread {
    private static volatile int count; //volatile具有线程间的变量的可见性不具备原子性
    
    public void run(){
        addCount();
    }
    
    private  static void addCount() {
        for(int i = 0; i< 1000; i++){
            count++;
        }
        //System.out.println(count.get());
        System.out.println(count);
    }

    public static void main(String[] args) {
        VolatileNoAtomic[] atomics = new VolatileNoAtomic[10];
        for(int i = 0; i<10; i++){
            atomics[i] = new VolatileNoAtomic(); //创建10个线程
            atomics[i].start(); //启动10个线程
        }
    }
    /*
     *  1000
        2000
        3047
        4019
        4745
        5745
        6745
        7745
        8745
        9745
     */
}

2.

public class VolatileNoAtomic extends Thread {
    //  AtomicInteger 原子性
    private static AtomicInteger count = new AtomicInteger(0);
    public void run(){
        addCount();
    }
    
    private  static void addCount() {
        for(int i = 0; i< 1000; i++){
            count.incrementAndGet();
        }
        System.out.println(count.get());
    }

    public static void main(String[] args) {
        VolatileNoAtomic[] atomics = new VolatileNoAtomic[10];
        for(int i = 0; i<10; i++){
            atomics[i] = new VolatileNoAtomic(); //创建10个线程
            atomics[i].start(); //启动10个线程
        }
    }
    /*
     *  1000
        2000
        3611
        4796
        5543
        6495
        7699
        8000
        9751
        10000
     */
}