java - 如何理解AtomicInteger里的CAS操作？

Question

下面这个方法，我不理解

public final int getAndIncrement() {
    for (;;) {
        int current = get();
        int next = current + 1;
        if (compareAndSet(current, next))
            return current;
    }
}

为何要循环直到成功？如果这期间有另外的线程更改了value，导致compareAndSet（）返回false，那这就表面已经不是原子性了吧，还继续重复有啥意义？

Answer 1

It just wants to ensure that the write operation will not be overwritten, and there will be no calculation errors in multi-threaded situations. If you want to achieve atomicity as much as you want, you can only use locks, but this will be inefficient.