Lambda Expression – Iterating Map and List in Java 8

I have already covered normal way of iterating Map and list in Java. In this tutorial, we will see how to iterate (loop) Map and List in Java 8 using Lambda expression.

Iterating Map in Java 8 using Lambda expression

package com.beginnersbook;
import java.util.HashMap;
import java.util.Map;
public class IterateMapUsingLambda {
	public static void main(String[] args) {
		Map<String, Integer> prices = new HashMap<>();
		prices.put("Apple", 50);
		prices.put("Orange", 20);
		prices.put("Banana", 10);
		prices.put("Grapes", 40);
		prices.put("Papaya", 50);
		
		/* Iterate without using Lambda
		   for (Map.Entry<String, Integer> entry : prices.entrySet()) {
		   System.out.println("Fruit: " + entry.getKey() + ", Price: " + entry.getValue());
		   }
		*/ 
		
		prices.forEach((k,v)->System.out.println("Fruit: " + k + ", Price: " + v));

	}
}

Output:

Fruit: Apple, Price: 50
Fruit: Grapes, Price: 40
Fruit: Papaya, Price: 50
Fruit: Orange, Price: 20
Fruit: Banana, Price: 10

Iterating List in Java 8 using Lambda expression

package com.beginnersbook;
import java.util.List;
import java.util.ArrayList;
public class IterateListUsingLambda {
	public static void main(String[] argv) {
		List names = new ArrayList<>();
		names.add("Ajay");
		names.add("Ben");
		names.add("Cathy");
		names.add("Dinesh");
		names.add("Tom");
		
		/* Iterate without using Lambda
		 Iterator iterator = names.iterator();
		 while (iterator.hasNext()) {
			System.out.println(iterator.next());
		 } 
		*/ 
		names.forEach(name->System.out.println(name));
	}
}

Output:

Ajay
Ben
Cathy
Dinesh
Tom