CodesJava

Easy learning with example program codes

how to iterate hashmap in java?


HashMap

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

We can use iterator interface. It is a universal iterator as we can apply it to any Collection object. It provides the functionality of read and remove operations. Collection interface provides iterator() method to get the Iterator object. Iterator interface have following to methods to iterate collection objects.

hasNext(): It returns true if the iteration has more elements.
next(): It returns the next element in the iteration.

Example

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

Output

Highest salary emp: Name: Mahesh, Salary: 80000
Sign Up/ Sign In
Ask a Question


Copyright © 2018 CodesJava DMCA.com Protection Status SiteMap Reference: Java Wiki