}
                throw new DictionaryException("Failed to write a userDict file.", e);
            }
            item = newItem;
        }

        /**
         * Writes a character mapping item to the temporary file.
         *
         * @param oldItem the existing mapping item to process
         * @return the mapping item that was written, or null if the item was deleted
         */

                throw new DictionaryException("Failed to write a userDict file.", e);
            }
            item = newItem;
        }

        /**
         * Writes a stemmer override item to the temporary file.
         * If the item is being updated, it writes the new version.
         *
         * @param oldItem The original item from the dictionary.
         * @return The written item, or null if the item was deleted.