How to iterate map in java

In this example, we are going learn about what all the different ways to iterate Map in java.

File Name :MapIteration.java

/**
 * This program explains different ways to loop Map in Java
 */
package com.becbe.java;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;



/**
 * @author BECBE
 *
 */
public class MapIteration {

 /**
  * @param args
  */
 public static void main(String[] args) {
  
  //Map object declaration for employee 
  Map employeeMap = new HashMap();
  //Adding 4 employee details
  employeeMap.put("002345","Jake Merlin");
  employeeMap.put("002475","Mike charle");
  employeeMap.put("006345","Justin Renold");
  employeeMap.put("002425","Kate");
  
  System.out.println("Size of the Employee Map :"+employeeMap.size());
  
  
  System.out.println("Type 1: using Iterator");
  Iterator iterator = employeeMap.entrySet().iterator();
  while (iterator.hasNext()) {
   Map.Entry mapEntry = (Map.Entry) iterator.next();
   System.out.println("The key is : " + mapEntry.getKey()
    + ",value is :" + mapEntry.getValue());
  }
  
  System.out.println("Type 2 - Using entry set");
  
  for (Map.Entry entry : employeeMap.entrySet()) {
   System.out.println("Key : " + entry.getKey() + " Value : "
    + entry.getValue());
  }
  
  System.out.println("Type 3 using Key set");
  for (Object key : employeeMap.keySet()) {
   System.out.println("Key : " + key.toString() + " Value : "
    + employeeMap.get(key));
  }
  }
}

Output :

Size of the Employee Map :4
Type 1: using Iterator
The key is : 002475,value is :Mike charle
The key is : 002345,value is :Jake Merlin
The key is : 002425,value is :Kate
The key is : 006345,value is :Justin Renold
Type 2 - Using entry set
Key : 002475 Value : Mike charle
Key : 002345 Value : Jake Merlin
Key : 002425 Value : Kate
Key : 006345 Value : Justin Renold
Type 3 using Key set
Key : 002475 Value : Mike charle
Key : 002345 Value : Jake Merlin
Key : 002425 Value : Kate
Key : 006345 Value : Justin Renold

SHARE

Onlinecodegeek