In this tutorial, we will learn how to sort a list using using Comparator interface and Lambda expression. Rewrite Traditional For Loops with Stream and Lambda expression in Java
Sort the List of Objects using Comparator and Lambda expression in Java 8 Click To Tweet
Let’s consider we have a list of objects, and we want to sort them based on a specific attribute. Here’s an example using the Comparator interface and lambda expressions in Java:
Assuming we have a class Student with attributes name and age:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 | import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; /** * Using Java 8, Sort the List of Objects using Comparator and Lambda expression * @author Deepak Verma * */ public class Sort_List_of_Objects_using_Comparator_and_Lambda_expression_Java8 { public static void main(String[] args) { // Create a list of Student objects List<Student> studentList = new ArrayList<>(); studentList.add(new Student("Yashi", 19)); studentList.add(new Student("Isha", 33)); studentList.add(new Student("Gaurangee", 21)); studentList.add(new Student("Yashu", 18)); studentList.add(new Student("Deepak", 36)); // Sort the list based on age using Comparator and lambda expression Collections.sort(studentList, Comparator.comparingInt(Student::getAge)); // Print the sorted list studentList.forEach(student -> System.out.println(student.getName() + " - " + student.getAge())); } } class Student { private String name; private int age; public Student(String name, int age) { this.name = name; this.age = age; } public String getName() { return name; } public int getAge() { return age; } } |
In the above example:
- The
Studentclass has anameandage. - The
Comparator.comparingInt(Student::getAge)creates a comparator that comparesStudentobjects based on theirageattribute. Collections.sort(studentList, ...)sorts thestudentListusing the specified comparator.
Output:
1 2 3 4 5 | Yashu - 18 Yashi - 19 Gaurangee - 21 Isha - 33 Deepak - 36 |
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It demonstrates how we can use the Comparator interface and lambda expressions to sort a list of objects based on a specific attribute.
Sort the List using Comparator and Lambda in Java 8..!!! Click To Tweet
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