public void clear() {
        long delta = 0L; // negative number of deletions
        int i = 0;
        Node<K,V>[] tab = table;
        while (tab != null && i < tab.length) {
            int fh;
            Node<K,V> f = tabAt(tab, i);
            if (f == null)
                ++i;
            else if ((fh = f.hash) == MOVED) {
                tab = helpTransfer(tab, f);
                i = 0; // restart
            }
            else {
                synchronized (f) {
                    if (tabAt(tab, i) == f) {
                        Node<K,V> p = (fh >= 0 ? f :
                                       (f instanceof TreeBin) ?
                                       ((TreeBin<K,V>)f).first : null);
                        while (p != null) {
                            --delta;
                            p = p.next;
                        }
                        setTabAt(tab, i++, null);
                    }
                }
            }
        }
        if (delta != 0L)
            addCount(delta, -1);
    }
public void clear()