Different ways to iterate over a map using for-each loop

In this post, I am going explain the two approaches to iterate over a map using for-each loop.

 

Approach 1: for-each loop with Map entrySet

for (Map.Entry<Integer, String> entry : numbersMap.entrySet()) {
	System.out.printf("%d --> %s\n", entry.getKey(), entry.getValue());
}

 

Approach 2L for-each loop with Map keyset.

for (Integer key : numbersMap.keySet()) {
	System.out.printf("%d --> %s\n", key, numbersMap.get(key));
}

 

Find the below working application.

 

ForEachMapDemo.java

package com.sample.app;

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

public class ForEachMapDemo {

	public static void main(String[] args) {
		Map<Integer, String> numbersMap = new HashMap<>();

		numbersMap.put(1, "One");
		numbersMap.put(2, "Two");
		numbersMap.put(3, "Three");

		// Approach 1
		for (Map.Entry<Integer, String> entry : numbersMap.entrySet()) {
			System.out.printf("%d --> %s\n", entry.getKey(), entry.getValue());
		}

		System.out.println("\n\n");

		// Approach 2
		for (Integer key : numbersMap.keySet()) {
			System.out.printf("%d --> %s\n", key, numbersMap.get(key));
		}
	}

}

 

Output

1 --> One
2 --> Two
3 --> Three



1 --> One
2 --> Two
3 --> Three

   

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