Java Program to Sort LinkedHashMap By Values

09 Jun, 2021
The LinkedHashMap is just like HashMap with an additional feature of maintaining an order of elements inserted into it. HashMap provided the advantage of quick insertion, search, and deletion, but it never maintained the track and order of insertion which the LinkedHashMap provides where the elements can be accessed in their insertion order. 
Hence LinkedHashMap Is the child class of HashMap. Now, in LinkedHashMap insertion order has to be maintained, so convert the LinkedHashMap into a list and after that print the list in which values are in sorted order.
Illustration:
Input : LinkedHashMap = {{“for”, 2}, {“Geek”, 3}, {“Geeks”, 1}}
Output:  
Key -> Geeks : value -> 1
Key -> for : value -> 2
Key -> Geek : value ->3 
Procedure:
Create an object of LinkedHashMap Class where the object is declared of type Integer and String.Add elements to the above object created of the map using the put() method. Elements here are key-value pairs.Retrieve above all entries from the map and convert them to a list using entrySet() method.Sort the value of the list using the custom comparator.Now use the Collections class sort method inside which we are using a custom comparator to compare the value of a map.Print the above list object using for each loop.
Create an object of LinkedHashMap Class where the object is declared of type Integer and String.
Add elements to the above object created of the map using the put() method. Elements here are key-value pairs.
Retrieve above all entries from the map and convert them to a list using entrySet() method.
Sort the value of the list using the custom comparator.
Now use the Collections class sort method inside which we are using a custom comparator to compare the value of a map.
Print the above list object using for each loop.
Implementation:
Example 
Java
// java Program to Sort LinkedHashMap by Values // Importing all classes// from java.util packageimport java.util.*;import java.util.Collections;import java.util.Comparator;import java.util.LinkedHashMap; // Main Classclass GFG {     // Main driver method    public static void main(String[] args)    {         // Creating an object of LinkedHashMap Class        // Declaring object of Integer and String type        LinkedHashMap<String, Integer> map            = new LinkedHashMap<>();        // Adding elements to the object of Map        // using the put() method        // Elements here are key-value pairs        map.put("for", 2);        map.put("Geek", 3);        map.put("Geeks", 1);         // Now, getting all entries from map and        // convert it to a list using entrySet() method        List<Map.Entry<String, Integer> > list            = new ArrayList<Map.Entry<String, Integer> >(                map.entrySet());         // Using collections class sort method        // and inside which we are using        // custom comparator to compare value of map        Collections.sort(            list,            new Comparator<Map.Entry<String, Integer> >() {                // Comparing two entries by value                public int compare(                    Map.Entry<String, Integer> entry1,                    Map.Entry<String, Integer> entry2)                {                     // Substracting the entries                    return entry1.getValue()                        - entry2.getValue();                }            });         // Iterating over the sorted map        // using the for each method        for (Map.Entry<String, Integer> l : list) {             // Printing the sorted map            // using getKey()  and getValue() methods            System.out.println("Key ->"                               + " " + l.getKey()                               + ": Value ->"                               + l.getValue());        }    }}
Key -> Geeks: Value ->1
Key -> for: Value ->2
Key -> Geek: Value ->3
 
saurabh1990aror
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