EN
RU
ES
ZH
FR
DE
PT
AR
HI
stack_user51
·
How to sort an ArrayList of custom objects by a property (field) in Java?
Hello everyone! I'm a beginner Java developer and I'm having trouble sorting a list of objects.
I have a `User` class with fields `name` (String) and `age` (int). I create an `ArrayList`, add several users to it, and want to sort them by age (ascending). I tried using `Collections.sort(list)`, but the compiler complains that my `User` class does not implement the `Comparable` interface.
Here's my code:
```java
import java.util.ArrayList;
import java.util.Collections;
public class Main {
public static void main(String[] args) {
ArrayList users = new ArrayList<>();
users.add(new User("Alice", 30));
users.add(new User("Bob", 25));
users.add(new User("Charlie", 35));
// Compilation error
Co
