volatile测试问题

Question

运行下面的代码，按预期结果应该是：52，但是返回结果是 0

public class MyVolatile {
    private volatile static boolean[] account;

    public static void main(String[] args) {
        //1 init
        account = new boolean[100];
        Arrays.fill(account, false);

        //2 iterate
        ArrayList<Thread> arrayList = new ArrayList<Thread>();
        for (int i = 0; i < 52; i++) {
            Thread thread = new Thread(new Runnable() {
                @Override
                public void run() {
                    for (int j = 0; j < account.length; j++) {
                        System.out.println(Thread.currentThread() + " - " + j + ":" + account[j]);
                        if (account[j] == false) {
                            account[j] = true;
                            return;
                        }
                    }
                    System.out.println("no --- " + Thread.currentThread());
                }
            });
            arrayList.add(thread);
        }

        for (Thread thread : arrayList) {
            thread.start();
        }

        //3 end
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        int total = 0;
        for (int j = 0; j < 100; j++) {
            total = account[j] ? total + 1 : 0;
        }
        System.out.println("finally:" + total);
    }
}

为什么？为什么account数组里面全都是false？

如果把account数组的长度修改为52的话，结果total为：52。

当account数组的长度大于线程数时，结果总是为0。

Answer 1

total = account[j] ? total + 1 : 0;

后面的都是 false，直接给 total 赋值 0 了

你和隔壁的 https://segmentfault.com/q/10... 是一个人好几个小号么？问题差不多然而是两个人？