If you meant version specifically (not 4.x or 5.x), this post highlights the features that made that release line so popular.
// Bean to Map Map<String, Object> userMap = BeanUtil.beanToMap(user); hutool 39
Though the phrase "hutool 39" isn't an official version number, it represents a : the 3 layers of abstraction and 39 practical methods that eliminate the most common Java boilerplate. If you meant version specifically (not 4