Java 8 Stream Collectors groupingBy with sort Example

In this article we are going to see about Java 8 Stream Collectors  groupingBy with sort example program.

StreamGroupBy.java

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01.package com.javatutorialcorner.java8;

02. 

03.import java.util.ArrayList;

04.import java.util.LinkedHashMap;

05.import java.util.List;

06.import java.util.Map;

07.import java.util.function.Function;

08.import java.util.stream.Collectors;

09. 

10.public class StreamGroupBy {

11. 

12. public static void main(String[] args) {

13.  List<string> batsmanRanking = new ArrayList<>();

14.  batsmanRanking.add("Virat Kohli");

15.  batsmanRanking.add("AB de Villiers");

16.  batsmanRanking.add("David Warner");

17.  batsmanRanking.add("Joe Root");

18.  batsmanRanking.add("Kane Williamson");

19.  batsmanRanking.add("Quinton de Kock");

20.  batsmanRanking.add("AB de Villiers");

21.  batsmanRanking.add("Faf du Plessis");

22.  batsmanRanking.add("Virat Kohli");

23.  batsmanRanking.add("Babar Azam");

24.  batsmanRanking.add("Quinton de Kock");

25.  batsmanRanking.add("Martin Guptill");

26.  batsmanRanking.add("Shikhar Dhawan");

27.  batsmanRanking.add("AB de Villiers");

28.  batsmanRanking.add("Virat Kohli");

29.  batsmanRanking.add("Faf du Plessis");

30. 

31.  System.out.println("Java 8 Group by a List and display the total count.");

32. 

33.  Map<string long=""> result = batsmanRanking.stream()

34.    .collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));

35. 

36.  System.out.println(result);

37.   

38.  System.out.println("Java 8 Group by a List and display the total count with sorted order.");

39.  Map<string long=""> sortedResult = new LinkedHashMap<>();

40. 

41.  // Sort a map and add to sortedResult

42.  result.entrySet().stream().sorted(Map.Entry.<string long="">comparingByValue().reversed())

43.    .forEachOrdered(e -> sortedResult.put(e.getKey(), e.getValue()));

44. 

45.  System.out.println(sortedResult);

46. }

47. 

48.}

49.</string></string></string></string>

Output

Java 8 Group by a List and display the total count.
{Faf du Plessis=2, Virat Kohli=3, Martin Guptill=1, Babar Azam=1, Quinton de Kock=2, Kane Williamson=1, AB de Villiers=3, Joe Root=1, Shikhar Dhawan=1, David Warner=1}
Java 8 Group by a List and display the total count with sorted order.
{Virat Kohli=3, AB de Villiers=3, Faf du Plessis=2, Quinton de Kock=2, Martin Guptill=1, Babar Azam=1, Kane Williamson=1, Joe Root=1, Shikhar Dhawan=1, David Warner=1}

Java Java 8 6/25/2017 06:38:00 am