How to sort a stream of numbers, strings & list in Java 8

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In this post, we will learn “How to sort a stream of numbers, strings and list in Java 8?”.

Sorting of a Stream in Java 8...!!! Share on X

In this tutorial, we are going to cover below topics:

Sorting of stream of number in Ascending(Natural) Order
Sorting of stream of number in Descending(Reverse) Order
Sorting of stream of string in Ascending Order
Sorting of stream of string in Descending Order
Sorting of stream of list in Ascending Order
Sorting of stream of list custom object in Ascending Order

Let’s begin:

1. Sort number in natural order

import java.util.Comparator;
import java.util.stream.Stream;
public class Number_Sort_Stream_Java8_Example1 {
    public static void main(String[] args) {
        System.out.println("Sorted stream of Numbers in Ascending Order Example");
        Stream <Integer> numberStream = Stream.of(54, 22, 78, 11, 9);
        numberStream.sorted(Comparator.naturalOrder())
            .forEach(System.out::println);
    }
}

import java.util.Comparator;

import java.util.stream.Stream;

public class Number_Sort_Stream_Java8_Example1 {

public static void main(String[] args) {

System.out.println("Sorted stream of Numbers in Ascending Order Example");

Stream <Integer> numberStream = Stream.of(54, 22, 78, 11, 9);

numberStream.sorted(Comparator.naturalOrder())

.forEach(System.out::println);

}

Output:

Sorted stream of Numbers in Ascending Order Example
9
11
22
54
78

Sorted stream of Numbers in Ascending Order Example

2. Sort number in reverse order

import java.util.Comparator;
import java.util.stream.Stream;
public class Number_Sort_Stream_Java8_Example2 {
    public static void main(String[] args) {
        System.out.println("Sorted stream of Numbers in Descending Order Example");
        Stream <Integer> numberStream = Stream.of(54, 22, 78, 11, 9);
        numberStream.sorted(Comparator.reverseOrder())
            .forEach(System.out::println);
    }
}

import java.util.Comparator;

import java.util.stream.Stream;

public class Number_Sort_Stream_Java8_Example2 {

public static void main(String[] args) {

System.out.println("Sorted stream of Numbers in Descending Order Example");

Stream <Integer> numberStream = Stream.of(54, 22, 78, 11, 9);

numberStream.sorted(Comparator.reverseOrder())

.forEach(System.out::println);

}

Output:

Sorted stream of Numbers in Descending Order Example
78
54
22
11
9

Sorted stream of Numbers in Descending Order Example

3. Sort string in natural order

import java.util.Comparator;
import java.util.stream.Stream;
public class String_Sort_Stream_Java8_Example1 {
    
    public static void main(String[] args) {
    
        System.out.println("Sorted stream of Strings in Ascending Order Example");
        Stream <String> stringStream = Stream.of("Tom", "Mark", "Lucas", "Amber", "Cash", "Joey");
        stringStream.sorted(Comparator.naturalOrder())
            .forEach(System.out::println);
    }
}

import java.util.Comparator;

import java.util.stream.Stream;

public class String_Sort_Stream_Java8_Example1 {

public static void main(String[] args) {

System.out.println("Sorted stream of Strings in Ascending Order Example");

Stream <String> stringStream = Stream.of("Tom", "Mark", "Lucas", "Amber", "Cash", "Joey");

stringStream.sorted(Comparator.naturalOrder())

.forEach(System.out::println);

}

Output:

Sorted stream of Strings in Ascending Order Example
Amber
Cash
Joey
Lucas
Mark
Tom

Sorted stream of Strings in Ascending Order Example

Amber

Cash

Joey

Lucas

Mark

Tom

4. Sort string in reverse order

import java.util.Comparator;
import java.util.stream.Stream;
public class String_Sort_Stream_Java8_Example2 {
    
    public static void main(String[] args) {
    
        System.out.println("Sorted stream of Strings in Descending Order Example");
        Stream <String> stringStream = Stream.of("Tom", "Mark", "Lucas", "Amber", "Cash", "Joey");
        stringStream.sorted(Comparator.reverseOrder())
            .forEach(System.out::println);
    }
}

import java.util.Comparator;

import java.util.stream.Stream;

public class String_Sort_Stream_Java8_Example2 {

public static void main(String[] args) {

System.out.println("Sorted stream of Strings in Descending Order Example");

Stream <String> stringStream = Stream.of("Tom", "Mark", "Lucas", "Amber", "Cash", "Joey");

stringStream.sorted(Comparator.reverseOrder())

.forEach(System.out::println);

}

Output:

Sorted stream of Strings in Descending Order Example
Tom
Mark
Lucas
Joey
Cash
Amber

Sorted stream of Strings in Descending Order Example

Tom

Mark

Lucas

Joey

Cash

Amber

5. Sort list in natural order

import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
public class List_Sort_Stream_Java8_Example1 {
    public static void main(String[] args) {
        List <String> listOfStudents = Arrays.asList("Tom", "Mark", "Lucas", "Amber", "Cash", "Joey");
        System.out.println("Before Sorting:\n");
        for (String s: listOfStudents) {
            System.out.println(s);
        }
        System.out.println("\nAfter Sorting:\n");
        //Sort the list directly using Lambda expression
        listOfStudents.stream().sorted(Comparator.naturalOrder())
            .forEach(System.out::println);;
    }
}

import java.util.Arrays;

import java.util.Comparator;

import java.util.List;

public class List_Sort_Stream_Java8_Example1 {

public static void main(String[] args) {

List <String> listOfStudents = Arrays.asList("Tom", "Mark", "Lucas", "Amber", "Cash", "Joey");

System.out.println("Before Sorting:\n");

for (String s: listOfStudents) {

System.out.println(s);

}

System.out.println("\nAfter Sorting:\n");

//Sort the list directly using Lambda expression

listOfStudents.stream().sorted(Comparator.naturalOrder())

.forEach(System.out::println);;

}

Output:

Before Sorting:
Tom
Mark
Lucas
Amber
Cash
Joey
After Sorting:
Amber
Cash
Joey
Lucas
Mark
Tom

Before Sorting:

Tom

Mark

Lucas

Amber

Cash

Joey

After Sorting:

Amber

Cash

Joey

Lucas

Mark

Tom

6. Sort custom list object

import java.util.ArrayList;
import java.util.List;
public class List_Sort_Stream_Java8_Example2 {
    public static void main(String[] args) {
        List <Actor> listOfActors = getActors();
        System.out.println("Before Sorting:\n");
        for (Actor actor: listOfActors) {
            System.out.println(actor.getAge() + "---" + actor.getName());
        }
        System.out.println("\nAfter Sorting:\n");
        //Sort the list directly using Lambda expression
        listOfActors.sort((Actor a1, Actor a2) -> a1.getAge() - a2.getAge());
        //Print the sorted list using Java 8 foreach method
        listOfActors.forEach((actor) -> System.out.println(actor.getAge() + "---" + actor.getName()));
    }
    static List <Actor> getActors() {
        List <Actor> actors = new ArrayList <Actor> ();
        actors.add(new Actor(5, "yashu"));
        actors.add(new Actor(64, "gaurangee"));
        actors.add(new Actor(22, "pulkit"));
        actors.add(new Actor(93, "isha"));
        actors.add(new Actor(8, "deepak"));
        actors.add(new Actor(44, "yogi"));
        actors.add(new Actor(87, "yashi"));
        return actors;
    }
}

class Actor {
    int age;
    String name;
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

    public Actor(int age, String name) {
        this.name = name;
        this.age = age;
    }

}

import java.util.ArrayList;

import java.util.List;

public class List_Sort_Stream_Java8_Example2 {

public static void main(String[] args) {

List <Actor> listOfActors = getActors();

System.out.println("Before Sorting:\n");

for (Actor actor: listOfActors) {

System.out.println(actor.getAge() + "---" + actor.getName());

}

System.out.println("\nAfter Sorting:\n");

//Sort the list directly using Lambda expression

listOfActors.sort((Actor a1, Actor a2) -> a1.getAge() - a2.getAge());

//Print the sorted list using Java 8 foreach method

listOfActors.forEach((actor) -> System.out.println(actor.getAge() + "---" + actor.getName()));

}

static List <Actor> getActors() {

List <Actor> actors = new ArrayList <Actor> ();

actors.add(new Actor(5, "yashu"));

actors.add(new Actor(64, "gaurangee"));

actors.add(new Actor(22, "pulkit"));

actors.add(new Actor(93, "isha"));

actors.add(new Actor(8, "deepak"));

actors.add(new Actor(44, "yogi"));

actors.add(new Actor(87, "yashi"));

return actors;

}

class Actor {

int age;

String name;

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public Actor(int age, String name) {

this.name = name;

this.age = age;

}

Output:

Before Sorting:
5---yashu
64---gaurangee
22---pulkit
93---isha
8---deepak
44---yogi
87---yashi
After Sorting:
5---yashu
8---deepak
22---pulkit
44---yogi
64---gaurangee
87---yashi
93---isha

Before Sorting:

5---yashu

64---gaurangee

22---pulkit

93---isha

8---deepak

44---yogi

87---yashi

After Sorting:

5---yashu

8---deepak

22---pulkit

44---yogi

64---gaurangee

87---yashi

93---isha

See, how elegant and powerful Java 8 is.

Sorting of a Stream in Java 8...!!! Share on X

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Deepak Verma
Deepak Verma is a Test Automation Consultant and Software development Engineer for more than 10 years. His mission is to help you become an In-demand full stack automation tester. He is also the founder of Techndeck, a blog and online coaching platform dedicated to helping you succeed with all the automation basics to advanced testing automation tricks.
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http://Techndeck.com deepak.rkgit@gmail.com Verma Deepak

How to sort a stream of numbers, strings & list in Java 8

1. Sort number in natural order

2. Sort number in reverse order

3. Sort string in natural order

4. Sort string in reverse order

5. Sort list in natural order

6. Sort custom list object

Other Useful References:

Author

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How to sort a stream of numbers, strings & list in Java 8

1. Sort number in natural order

2. Sort number in reverse order

3. Sort string in natural order

4. Sort string in reverse order

5. Sort list in natural order

6. Sort custom list object

Other Useful References:

Author

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