{
// We walk through the keys while we modify the hashtable. This
// is not legal, and the result of the enumaration is undefined,
// but we should not get any exception when enumerating and we
// should not get null or any key that was never added.
for (Enumeration e = ht.elements(); e.hasMoreElements(); )
{
String str = (String) e.nextElement();
if (str != null && !allElements.containsKey(str))
{
returnedOnlyElementsThatWerePut = false;