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how to create a linkedhashmap in java?


LinkedHashMap

LinkedHashMap extends HashMap class and implements the Map interface. It contains the elements in key-value pair form. It maintains insertion order for its elements. It not allowed duplicate key. A LinkedHashMap can have only one null key and multiple null values.

Example

package com.codesjava;
 
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
 
public class Test {
	public static void main(String args[]){
		LinkedHashMap<Integer, String> linkedHashMap = 
				new LinkedHashMap<Integer, String>();
 
		//Add objects to the HashSet.
		linkedHashMap.put(4, "Roxy");
		linkedHashMap.put(2, "Sunil");
		linkedHashMap.put(5, "Sandy");
		linkedHashMap.put(1, "Munish");
		linkedHashMap.put(3, "Pardeep");
 
		//Print the LinkedHashMap object.
		System.out.println("LinkedHashMap elements:");
		System.out.println(linkedHashMap);
 
		//Get iterator
		Set set=linkedHashMap.entrySet();  
		Iterator iterator=set.iterator();  
 
		//Print the LinkedHashMap elements using iterator.
		System.out.println("LinkedHashMap elements " +
				"using iterator:");
		while(iterator.hasNext()){
		   Map.Entry mapEntry=(Map.Entry)iterator.next();  
		   System.out.println("Key: " + mapEntry.getKey() + 
				   ", Value: " + mapEntry.getValue());  
		}  
	}
}

Output

LinkedHashMap elements:
{4=Roxy, 2=Sunil, 5=Sandy, 1=Munish, 3=Pardeep}
LinkedHashMap elements using iterator:
Key: 4, Value: Roxy
Key: 2, Value: Sunil
Key: 5, Value: Sandy
Key: 1, Value: Munish
Key: 3, Value: Pardeep


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