问ConcurrentBitSet中的竞赛条件

EN

public class ConcurrentBitSet {

static final int CELL = 32;
static final int MASK = CELL - 1;
final AtomicReference<AtomicIntegerArray> aiaRef;

public ConcurrentBitSet(int initialBitSize) {
    aiaRef = new AtomicReference<>(new AtomicIntegerArray(1 + ((initialBitSize - 1) / CELL)));
}

public boolean get(int bit) {
    int cell = bit / CELL;
    if (cell >= aiaRef.get().length()) {
        return false;
    }
    int mask = 1 << (bit & MASK);
    return (aiaRef.get().get(cell) & mask) != 0;
}

public void set(int bit) {
    int cell = bit / CELL;
    int mask = 1 << (bit & MASK);
    while (true) {
        AtomicIntegerArray old = aiaRef.get();
        AtomicIntegerArray v = extend(old, cell);
        v.getAndAccumulate(cell, mask, (prev, m) -> prev | m);
        if (aiaRef.compareAndSet(old, v)) {
            break;
        }
    }
}

private AtomicIntegerArray extend(AtomicIntegerArray old, int cell) {
    AtomicIntegerArray v = old;
    if (cell >= v.length()) {
        v = new AtomicIntegerArray(cell + 1);
        for (int i = 0; i < old.length(); i++) {
            v.set(i, old.get(i));
        }
    }
    return v;
}

public String toString() {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < aiaRef.get().length(); i++) {
        for (int b = 0; b < CELL; b++) {
            sb.append(get(i * CELL + b) ? '1' : '0');
        }
    }
    return sb.toString();
}

}

    final ConcurrentBitSet cbs = new ConcurrentBitSet(10);
    CountDownLatch latch = new CountDownLatch(1);
    new Thread() {
        public void run() {
            try {
                latch.await();
                for (int i = 0; i < 300; i += 2) {
                    cbs.set(i);
                }
            } catch (InterruptedException e) {

            }
        };
    }.start();
    new Thread() {
        public void run() {
            try {
                latch.await();
                for (int i = 0; i < 300; i += 2) {
                    cbs.set(i + 1);
                }
            } catch (InterruptedException e) {
            }
        };
    }.start();
    latch.countDown();
    Thread.sleep(1000);
    System.out.println(cbs.toString());