Tuesday, 3 May 2016

How to Iterate over a ArrayList using Lambda Expression in Java 8

Iterate over a ArrayList using Lambda Expression

Using the Lambda Expression feature in Java 8 we can easily iterate over a list of items easily.
This can be done in this way.

Example 1. Simply Iterate over a List and Print the Items.

import java.util.ArrayList;
import java.util.List;

public class IterateList {

 public static void main(String[] args) {
  List items = new ArrayList<>();
  items.add("Hello");
  items.add("Java");
  items.add("Welcome");
  items.add("to");
  items.add("Codermagnet");

  //iterate list and print the items
  items.forEach(System.out::println);

 }
}


Output:
Hello
Java
Welcome
to
Codermagnet


Example 2. Iterate over a List and do operations on the list items.

import java.util.ArrayList;
import java.util.List;

public class IterateList {

 public static void main(String[] args) {
  List items = new ArrayList<>();
  items.add("Hello");
  items.add("Java");
  items.add("Welcome");
  items.add("to");
  items.add("Codermagnet");
  
  //Iterate over a list and call a function
  //items.forEach(item -> System.out.println(item));
  //OR like this 
  items.forEach(item -> printData(item));

 }

 public static void printData(String item) {
  System.out.println("Hello " + item);
  //Your Business Logic here
 }
}


Output:
Hello Hello
Hello Java
Hello Welcome
Hello to
Hello Codermagnet