HashIterator(Type<R, K, V> type) 
{
            this.type = type;
            expectedModCount = modCount;
}

 public boolean hasNext() 
{
            if (nextEntry != null && (nextKey != null || nextEntry.isNull)) {
                return true;
            }
            while (true) {
                if (nextEntry == null) {
                    while (position <  elementData.length) {
                        if ((nextEntry = elementData[position++]) != null) {
                            break;
                        }
                    }
                    if (nextEntry == null) {
                        return false;
                    }
                }
                // ensure key of next entry is not gc'ed
                nextKey = nextEntry.get();
                if (nextKey != null || nextEntry.isNull) {
                    return true;
                }
                nextEntry = nextEntry.next;
            }
}

 public R next() 
{
            if (expectedModCount == modCount) {
                if (hasNext()) {
                    currentEntry = nextEntry;
                    nextEntry = currentEntry.next;
                    R result = type.get(currentEntry);
                    // free the key
                    nextKey = null;
                    return result;
                }
                throw new NoSuchElementException();
            }
            throw new ConcurrentModificationException();
}

 public  void remove() 
{
            if (expectedModCount == modCount) {
                if (currentEntry != null) {
                    removeEntry(currentEntry);
                    currentEntry = null;
                    expectedModCount++;
                    // cannot poll() as that would change the expectedModCount
                } else {
                    throw new IllegalStateException();
                }
            } else {
                throw new ConcurrentModificationException();
            }
}