// Create test input stream
        String content = "updated1\n" + "updated2\n";
        InputStream is = new ByteArrayInputStream(content.getBytes(StandardCharsets.UTF_8));

        // Update from input stream
        protwordsFile.update(is);

        // Verify update
        PagingList<ProtwordsItem> list = protwordsFile.selectList(0, 100);
        assertEquals(2, list.size());

        try (MappingUpdater updater = new MappingUpdater(item)) {
            reload(updater);
        }
    }

    /**
     * Reloads the character mapping items from the dictionary file.
     *
     * @param updater the mapping updater to use for writing changes, or null for read-only reload
     */
    protected void reload(final MappingUpdater updater) {

        try (ProtwordsUpdater updater = new ProtwordsUpdater(item)) {
            reload(updater);
        }
    }

    /**
     * Reloads the dictionary file with the specified updater.
     * @param updater the updater to use for processing items
     */
    protected void reload(final ProtwordsUpdater updater) {

        assertNull(result);

        updater.close();
    }

    public void test_updater_writeLine() {
        StopwordsFile.StopwordsUpdater updater = stopwordsFile.new StopwordsUpdater(null);

        // Test writing a comment line
        updater.write("# This is a comment");

        updater.close();
    }

    // Test edge cases
    public void test_emptyFile() {

        kuromojiItem.setNewToken(StringUtil.EMPTY);
        try (KuromojiUpdater updater = new KuromojiUpdater(item)) {
            reload(updater);
        }
    }

    /**
     * Reloads the dictionary file.
     *
     * @param updater The updater.
     */
    protected void reload(final KuromojiUpdater updater) {
        try (CurlResponse curlResponse = dictionaryManager.getContentResponse(this)) {

    public synchronized void insert(final StopwordsItem item) {
        try (StopwordsUpdater updater = new StopwordsUpdater(item)) {
            reload(updater);
        }
    }

    @Override
    public synchronized void update(final StopwordsItem item) {
        try (StopwordsUpdater updater = new StopwordsUpdater(item)) {
            reload(updater);
        }
    }

    @Override

        try (StemmerOverrideUpdater updater = new StemmerOverrideUpdater(item)) {
            reload(updater);
        }
    }

    @Override
    public synchronized void update(final StemmerOverrideItem item) {
        try (StemmerOverrideUpdater updater = new StemmerOverrideUpdater(item)) {
            reload(updater);
        }
    }

    @Override

    public synchronized void insert(final SynonymItem item) {
        try (SynonymUpdater updater = new SynonymUpdater(item)) {
            reload(updater);
        }
    }

    @Override
    public synchronized void update(final SynonymItem item) {
        try (SynonymUpdater updater = new SynonymUpdater(item)) {
            reload(updater);
        }
    }

    @Override

  }

  /**
   * Atomically updates the element at index {@code i} with the results of applying the given
   * function to the current and given values.
   *
   * @param i the index to update
   * @param x the update value
   * @param accumulatorFunction the accumulator function
   * @return the updated value
   * @since 31.1
   */
  @CanIgnoreReturnValue

  /**
   * Computes the function of current and new value. Subclasses should open-code this update
   * function for most uses, but the virtualized form is needed within retryUpdate.
   *
   * @param currentValue the current value (of either base or a cell)
   * @param newValue the argument from a user update call
   * @return result of the update function
   */
  abstract long fn(long currentValue, long newValue);

  /**