How to sort objects in java using Comparator?

In the below example class Student has three fields

Name, Age & Mark

Now i am showing 2 types of sorting here

1. by Name
2. by Mark

Comparator is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference. This interface is a member of the Java Collections Framework.

import java.util.ArrayList; import java.util.Collections; class Students { String name; int mark; int age; public Students(String name, int mark, int age) { this.name = name; this.mark = mark; this.age = age; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getMark() { return mark; } public void setMark(int mark) { this.mark = mark; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } } public class BitCompiler { public static void main(String args[]) { ArrayList<Students> students = new ArrayList<>(); students.add(new Students("Smith", 87, 16)); students.add(new Students("Johnson", 92, 15)); students.add(new Students("Srank", 95, 17)); students.add(new Students("Kamal", 99, 18)); students.add(new Students("George Vaman", 96, 17)); System.out.println("\nSorting by Student Name:\n========================"); Collections.sort(students,(a,b)-> { return a.getName().compareTo(b.getName()); }); students.forEach(a -> { System.out.println("Name = "+a.getName());}); System.out.println("\nSorting by Student Mark:\n========================"); Collections.sort(students,(a,b)-> { return a.getMark() > b.getMark() ? -1 : a.getMark() < b.getMark() ? 1 : 0; }); students.forEach(a -> { System.out.println("Name = "+a.getName()+", Mark = "+a.getMark());}); } }

Output: