final KuromojiFile kuromojiFile = new KuromojiFile(file1);
        final PagingList<KuromojiItem> itemList1 = kuromojiFile.selectList(0,
                20);
        assertEquals(3, itemList1.size());

        final KuromojiItem kuromojiItem1 = itemList1.get(0);
        kuromojiFile.delete(kuromojiItem1);
        final PagingList<KuromojiItem> itemList2 = kuromojiFile.selectList(0,
                20);

        form.dictId = dictId;
        validateApi(form, messages -> {});
        final KuromojiFile file = kuromojiService.getKuromojiFile(form.dictId).orElseGet(() -> {
            throwValidationErrorApi(messages -> messages.addErrorsFailedToUploadProtwordsFile(GLOBAL));
            return null;
        });
        try (InputStream inputStream = form.kuromojiFile.getInputStream()) {
            file.update(inputStream);

     * @return An optional entity of the Kuromoji file.
     */
    public OptionalEntity<KuromojiFile> getKuromojiFile(final String dictId) {
        return dictionaryManager.getDictionaryFile(dictId)
                .filter(KuromojiFile.class::isInstance)
                .map(file -> OptionalEntity.of((KuromojiFile) file))
                .orElse(OptionalEntity.empty());
    }

    /**
     * Get a Kuromoji item.

                                    <label for="kuromojiFile" class="col-sm-3 text-sm-right col-form-label"><la:message
                                            key="labels.dict_kuromoji_file"/></label>
                                    <div class="col-sm-9">
                                        <input type="file" id="kuromojiFile" name="kuromojiFile" class="form-control-file"/>
                                    </div>

     * @return A new dictionary file.
     */
    @Override
    protected DictionaryFile<? extends DictionaryItem> newDictionaryFile(final String id, final String path, final Date timestamp) {
        return new KuromojiFile(id, path, timestamp).manager(dictionaryManager);
    }

     * This file should be in the Kuromoji user dictionary format containing custom word definitions.
     */
    @Required
    public MultipartFormFile kuromojiFile;

    /**
     * Default constructor for UploadForm.
     * Creates a new instance with default values.
     */
    public UploadForm() {
        // Default constructor
    }