/**
* Removes the pair whose key is Object equal to <code>key</code> from <code>hashCodeMap</code>,
* provided that <code>key</code>'s hash code is <code>hashCode</code>. Returns the value that was
* associated with the removed key, or null if no such key existed.
*/
private V removeHashValue(Object key) {
return hashCodeMap.remove(key);
}
