How to Sort a Map by Key & Value in Java 8

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In this tutorial, we will see “How to sort a Map by Key & Value in Java 8 using LinkedHashMap?”

Approach/Steps:

1. Create a Map object and add values to it.
 
2. Convert Map object into a Stream.
3. Sort it now.
4. Finally, either collect it with LinkedHashMap OR perform the forEachOrdered operation with LinkedHashMap.

1. Create a Map object and add values to it.

2. Convert Map object into a Stream.

3. Sort it now.

4. Finally, either collect it with LinkedHashMap OR perform the forEachOrdered operation with LinkedHashMap.

Sort a Map in Java 8 with examples...!!! Share on X

Example 1. Sort Map by Key using LinkedHashMap with Collect

import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.stream.Collectors;
public class Sort_Map_ByKey_With_Collect_Java8 {
    public static void main(String[] argv) {
        Map <String, Integer> unsortedMapObj = new HashMap <> ();
        unsortedMapObj.put("Tom", 50);
        unsortedMapObj.put("Brett", 45);
        unsortedMapObj.put("Ashton", 9);
        unsortedMapObj.put("Claire", 78);
        unsortedMapObj.put("Daniella", 2);
        System.out.println("Original Unsorted Map: \n" + unsortedMapObj);
        Map <String, Integer> sortedMapObj = unsortedMapObj
            .entrySet()
            .stream()
            .sorted(Map.Entry.comparingByKey())
            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (oldValue, newValue) -> oldValue, LinkedHashMap::new));
        System.out.println("\nResulted Sorted Map by Key in ascending order: \n" + sortedMapObj);
    }
}

import java.util.HashMap;

import java.util.LinkedHashMap;

import java.util.Map;

import java.util.stream.Collectors;

public class Sort_Map_ByKey_With_Collect_Java8 {

public static void main(String[] argv) {

Map <String, Integer> unsortedMapObj = new HashMap <> ();

unsortedMapObj.put("Tom", 50);

unsortedMapObj.put("Brett", 45);

unsortedMapObj.put("Ashton", 9);

unsortedMapObj.put("Claire", 78);

unsortedMapObj.put("Daniella", 2);

System.out.println("Original Unsorted Map: \n" + unsortedMapObj);

Map <String, Integer> sortedMapObj = unsortedMapObj

.entrySet()

.stream()

.sorted(Map.Entry.comparingByKey())

.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (oldValue, newValue) -> oldValue, LinkedHashMap::new));

System.out.println("\nResulted Sorted Map by Key in ascending order: \n" + sortedMapObj);

}

Output:

Original Unsorted Map: 
{Claire=78, Brett=45, Tom=50, Daniella=2, Ashton=9}
Resulted Sorted Map by Key in ascending order: 
{Ashton=9, Brett=45, Claire=78, Daniella=2, Tom=50}

Original Unsorted Map:

{Claire=78, Brett=45, Tom=50, Daniella=2, Ashton=9}

Resulted Sorted Map by Key in ascending order:

{Ashton=9, Brett=45, Claire=78, Daniella=2, Tom=50}

Example 2. Sort Map by Key using LinkedHashMap with ForEachOrdered

import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
public class Sort_Map_ByKey_With_ForEachOrdered_Java8 {
    public static void main(String[] args) {
        Map <String, Integer> unsortedMapObj = new HashMap <> ();
        unsortedMapObj.put("Tom", 50);
        unsortedMapObj.put("Brett", 45);
        unsortedMapObj.put("Ashton", 9);
        unsortedMapObj.put("Claire", 78);
        unsortedMapObj.put("Daniella", 2);
        System.out.println("Original Unsorted Map: \n" + unsortedMapObj);
        Map <String, Integer> sortedMapObj = new LinkedHashMap <> ();
        unsortedMapObj.entrySet()
            .stream()
            .sorted(Map.Entry.comparingByKey())
            .forEachOrdered(i -> sortedMapObj.put(i.getKey(), i.getValue()));
        System.out.println("\nResulted Sorted Map by Key in ascending order: \n" + sortedMapObj);
    }
}

import java.util.HashMap;

import java.util.LinkedHashMap;

import java.util.Map;

public class Sort_Map_ByKey_With_ForEachOrdered_Java8 {

public static void main(String[] args) {

Map <String, Integer> unsortedMapObj = new HashMap <> ();

unsortedMapObj.put("Tom", 50);

unsortedMapObj.put("Brett", 45);

unsortedMapObj.put("Ashton", 9);

unsortedMapObj.put("Claire", 78);

unsortedMapObj.put("Daniella", 2);

System.out.println("Original Unsorted Map: \n" + unsortedMapObj);

Map <String, Integer> sortedMapObj = new LinkedHashMap <> ();

unsortedMapObj.entrySet()

.stream()

.sorted(Map.Entry.comparingByKey())

.forEachOrdered(i -> sortedMapObj.put(i.getKey(), i.getValue()));

System.out.println("\nResulted Sorted Map by Key in ascending order: \n" + sortedMapObj);

}

Output:

Original Unsorted Map: 
{Claire=78, Brett=45, Tom=50, Daniella=2, Ashton=9}
Resulted Sorted Map by Key in ascending order: 
{Ashton=9, Brett=45, Claire=78, Daniella=2, Tom=50}

Original Unsorted Map:

{Claire=78, Brett=45, Tom=50, Daniella=2, Ashton=9}

Resulted Sorted Map by Key in ascending order:

{Ashton=9, Brett=45, Claire=78, Daniella=2, Tom=50}

Example 3. Sort Map by Value using LinkedHashMap with Collect

import java.util.Comparator;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.stream.Collectors;
public class Sort_Map_ByValue_With_Collect_Java8 {
    public static void main(String[] argv) {
        Map <String, Integer> unsortedMapObj = new HashMap <> ();
        unsortedMapObj.put("Tom", 50);
        unsortedMapObj.put("Brett", 45);
        unsortedMapObj.put("Ashton", 9);
        unsortedMapObj.put("Claire", 78);
        unsortedMapObj.put("Daniella", 2);
        System.out.println("Original Unsorted Map: \n" + unsortedMapObj);
        Map <String, Integer> sortedMapObj = unsortedMapObj.entrySet()
            .stream()
            .sorted(Map.Entry.comparingByValue(Comparator.naturalOrder()))
            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (oldValue, newValue) -> oldValue, LinkedHashMap::new));
        System.out.println("\nResulted Sorted Map by value in ascending order: \n" + sortedMapObj);
    }
}

import java.util.Comparator;

import java.util.HashMap;

import java.util.LinkedHashMap;

import java.util.Map;

import java.util.stream.Collectors;

public class Sort_Map_ByValue_With_Collect_Java8 {

public static void main(String[] argv) {

Map <String, Integer> unsortedMapObj = new HashMap <> ();

unsortedMapObj.put("Tom", 50);

unsortedMapObj.put("Brett", 45);

unsortedMapObj.put("Ashton", 9);

unsortedMapObj.put("Claire", 78);

unsortedMapObj.put("Daniella", 2);

System.out.println("Original Unsorted Map: \n" + unsortedMapObj);

Map <String, Integer> sortedMapObj = unsortedMapObj.entrySet()

.stream()

.sorted(Map.Entry.comparingByValue(Comparator.naturalOrder()))

.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (oldValue, newValue) -> oldValue, LinkedHashMap::new));

System.out.println("\nResulted Sorted Map by value in ascending order: \n" + sortedMapObj);

}

Output:

Original Unsorted Map: 
{Claire=78, Brett=45, Tom=50, Daniella=2, Ashton=9}
Resulted Sorted Map by value in ascending order: 
{Daniella=2, Ashton=9, Brett=45, Tom=50, Claire=78}

Original Unsorted Map:

{Claire=78, Brett=45, Tom=50, Daniella=2, Ashton=9}

Resulted Sorted Map by value in ascending order:

{Daniella=2, Ashton=9, Brett=45, Tom=50, Claire=78}

Example 4. Sort Map by Value using LinkedHashMap with ForEachOrdered

import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
public class Sort_Map_ByValue_With_ForEachOrdered_Java8 {
    public static void main(String[] argv) {
        Map <String, Integer> unsortedMapObj = new HashMap <> ();
        unsortedMapObj.put("Tom", 50);
        unsortedMapObj.put("Brett", 45);
        unsortedMapObj.put("Ashton", 9);
        unsortedMapObj.put("Claire", 78);
        unsortedMapObj.put("Daniella", 2);
        System.out.println("Original Unsorted Map: \n" + unsortedMapObj);
        Map <String, Integer> sortedMapObj = new LinkedHashMap <> ();
        unsortedMapObj.entrySet()
            .stream()
            .sorted(Map.Entry. <String, Integer> comparingByValue())
            .forEachOrdered(x -> sortedMapObj.put(x.getKey(), x.getValue()));
        System.out.println("\nResulted Sorted Map by value in ascending order: \n" + sortedMapObj);
    }
}

import java.util.HashMap;

import java.util.LinkedHashMap;

import java.util.Map;

public class Sort_Map_ByValue_With_ForEachOrdered_Java8 {

public static void main(String[] argv) {

Map <String, Integer> unsortedMapObj = new HashMap <> ();

unsortedMapObj.put("Tom", 50);

unsortedMapObj.put("Brett", 45);

unsortedMapObj.put("Ashton", 9);

unsortedMapObj.put("Claire", 78);

unsortedMapObj.put("Daniella", 2);

System.out.println("Original Unsorted Map: \n" + unsortedMapObj);

Map <String, Integer> sortedMapObj = new LinkedHashMap <> ();

unsortedMapObj.entrySet()

.stream()

.sorted(Map.Entry. <String, Integer> comparingByValue())

.forEachOrdered(x -> sortedMapObj.put(x.getKey(), x.getValue()));

System.out.println("\nResulted Sorted Map by value in ascending order: \n" + sortedMapObj);

}

Output:

Original Unsorted Map: 
{Claire=78, Brett=45, Tom=50, Daniella=2, Ashton=9}
Resulted Sorted Map by value in ascending order: 
{Daniella=2, Ashton=9, Brett=45, Tom=50, Claire=78}

Original Unsorted Map:

{Claire=78, Brett=45, Tom=50, Daniella=2, Ashton=9}

Resulted Sorted Map by value in ascending order:

{Daniella=2, Ashton=9, Brett=45, Tom=50, Claire=78}

Sort a Map in Java 8 with examples...!!! 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 Map by Key & Value in Java 8

Approach/Steps:

Example 1. Sort Map by Key using LinkedHashMap with Collect

Example 2. Sort Map by Key using LinkedHashMap with ForEachOrdered

Example 3. Sort Map by Value using LinkedHashMap with Collect

Example 4. Sort Map by Value using LinkedHashMap with ForEachOrdered

Other Useful References:

Author

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How to Sort a Map by Key & Value in Java 8

Approach/Steps:

Example 1. Sort Map by Key using LinkedHashMap with Collect

Example 2. Sort Map by Key using LinkedHashMap with ForEachOrdered

Example 3. Sort Map by Value using LinkedHashMap with Collect

Example 4. Sort Map by Value using LinkedHashMap with ForEachOrdered

Other Useful References:

Author

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