code: public Token removeFirst(Transaction transaction)
                      throws ObjectManagerException
      {
          Iterator iterator = entrySet().iterator();
          List.Entry entry = (List.Entry) iterator.next(transaction);
          iterator.remove(transaction);
          return entry.getValue();
      }
docs: Remove the first element in the list.
  
  @param transaction
  the transaction cotroling the ultimate removal.
  @return the object removed.
  @exception java.util.NoSuchElementException
  if there is nothing in the list or it has already been deleted by some other
  uncommited transaction.
  @throws ObjectManagerException.