code: protected synchronized void removeSemiUniqueEntry(SingleEntry key)
      {
          int hash = key.getSemiUniqueHash();
          SemiUniqueEntry[] tab = getNonDatedTable();
          int i = indexFor(hash, tab.length);
          SemiUniqueEntry prev = tab[i];
          SemiUniqueEntry e = prev;
  
          while (e != null)
          {
              SemiUniqueEntry next = e.getSemiUniqueNext();
              Object oldValue = e.removeEntryUsingIdentity(hash, key);
              if (oldValue != null)
              {
                  if (e.isEmptyAfterRemoval())
                  {
                      removeFromNonDatedTable(prev, e, next, tab, i);
                  }
                  return;
              }
              prev = e;
              e = next;
          }
      }
docs: /*
  Removes and returns the entry associated with the specified key
  in the HashMap.  Returns null if the HashMap contains no mapping
  for this key.