How to put objects with the same properties in the list collection into a new list

Today, I will talk to you about how to put objects with the same attributes in the list collection into a new list. Many people may not know much about it. In order to let everyone know more, Xiaobian summarizes the following contents for everyone. I hope everyone can gain something according to this article.

List result = new ArrayList();Map map = new HashMap();//userList is the list collection to operate on for (User user : userList) { Integer age = user.getAge(); List lstUser; if (map.containsKey(age)) { lstUser= map.get(age); }else{ lstUser= new ArrayList(); } lstUser.add(user); map.put(age,lstUser);}for (Map.Entry entry : map.entrySet()) { result.add(entry.getValue());} After reading the above, do you have any further understanding of how to put objects in a list collection with the same attributes into a new list? If you still want to know more knowledge or related content, please pay attention to the industry information channel, thank you for your support.