public class  extends Number implements java.io.Serializable {
    private static final long serialVersionUID = 6214790243416807050L;
    private static final Unsafe unsafe = Unsafe.getUnsafe();
    private static final long valueOffset;

    static {
        try {
            
            valueOffset = unsafe.objectFieldOffset
                (AtomicInteger.class.getDeclaredField("value"));
        } catch (Exception ex) { throw new Error(ex); }
    }

    private volatile int value;

    public final void lazySet(int newValue) {
        // 深度思考，这边为什么使用count = newValue
        // 因为"count = newValue"会插入storeLoad屏障
        // 而putOrderedInt插入的是storeStore屏障
        unsafe.putOrderedInt(this, valueOffset, newValue);
    }

    public final int getAndAdd(int delta) {
        return unsafe.getAndAddInt(this, valueOffset, delta);
    }

    public final int incrementAndGet() {
        return unsafe.getAndAddInt(this, valueOffset, 1) + 1;
    }

    public final int decrementAndGet() {
        return unsafe.getAndAddInt(this, valueOffset, -1) - 1;
    }

    public final int addAndGet(int delta) {
        return unsafe.getAndAddInt(this, valueOffset, delta) + delta;
    }
}