LinkedHashMap in java with example

In this post, we will see about LinkedHashMap in java. LinkedHashMap is same as HashMap except that it maintains insertion order.

Some points about LinkedHashMap

LinkedHashMap implements Map interface and extends HashMap class.
LinkedHashMap maintains insertion order, so when you will be able to access elements in the order they were inserted like ArrayList.
LinkedHashMap maintains doubly Linked list to maintain insertion order.

LinkedHashMapMain.java

package org.arpit.java2blog;

import java.util.LinkedHashMap;

public class LinkedHashMapMain {

public static void main(String args[])

{

// LinkedHashMap with Country as key and capital as value

// LinkedHashMap maintains insertion order

LinkedHashMap<String,String> countryCapitalMap=new LinkedHashMap<String,String>();

countryCapitalMap.put("India","Delhi");

countryCapitalMap.put("Japan","Tokyo");

countryCapitalMap.put("France","Paris");

countryCapitalMap.put("Russia","Moscow");

System.out.println("-----------------------------");

// Iterating Using keySet() and for each loop

System.out.println("Iterating Using keySet() and for each loop");

for (String countryKey:countryCapitalMap.keySet()) {

System.out.println("Country:"+ countryKey +" and Capital:"+countryCapitalMap.get(countryKey));

}

System.out.println("-----------------------------");

}

If you may iterate LinkedHashMap in multiple ways.
When you run above program, you will get below output:

-----------------------------

Iterating Using keySet() and for each loop

Country:India and Capital:Delhi

Country:Japan and Capital:Tokyo

Country:France and Capital:Paris

Country:Russia and Capital:Moscow

-----------------------------

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