private void updateBookFields(Book book, BookDto bookDto) { book.setAuthor(bookDto.getAuthor()); book.setDescription(bookDto.getDescription()); book.setBookLanguage(bookDto.getLanguage()); book.setPages(bookDto.getPages()); book.setTitle(bookDto.getTitle()); book.setYear(bookDto.getYear()); String categoryId = null; if (!bookDto.getCategory().equals("default")) categoryId = bookDto.getCategory(); book.setCategory(categoryId); }