private void put(final Item i) {
        if (index + typeCount > threshold) {
            int ll = items.length;
            int nl = ll * 2 + 1;
            Item[] newItems = new Item[nl];
            for (int l = ll - 1; l >= 0; --l) {
                Item j = items[l];
                while (j != null) {
                    int index = j.hashCode % newItems.length;
                    Item k = j.next;
                    j.next = newItems[index];
                    newItems[index] = j;
                    j = k;
                }
            }
            items = newItems;
            threshold = (int) (nl * 0.75);
        }
        int index = i.hashCode % items.length;
        i.next = items[index];
        items[index] = i;
    }