Java Program to Iterate over ArrayList using Lambda Expression

In this article, we will understand how to iterate over ArrayList using lambda expression. The ArrayList class is a resizable array, which can be found in the java.util package. The difference between a built-in array and an ArrayList in Java, is that the size of an array cannot be modified.

Below is a demonstration of the same −

Suppose our input is −

Run the program

The desired output would be −

The list is defined as: Java Python Scala Mysql Redshift

Algorithm

Step 1 - START
Step 2 - Declare namely
Step 3 - Define the values.
Step 4 - Create an ArrayList, and iterate over it, and display it.
Step 5 - In the ArrayList, add elements using the ‘add’ method.
Step 6 - Display this on the console.
Step 7 - Use the ‘forEach’ loop to iterate over the elements, and display them.
Step 8 - Stop

Example 1

Here, we bind all the operations together under the ‘main’ function.

import java.util.ArrayList;
public class Demo {
   public static void print(ArrayList<String> input_list) {
      System.out.print("\nThe list is defined as:\n ");
      for(String language : input_list) {
         System.out.print(language + " ");
      }
   }
   public static void main(String[] args) {
      System.out.println("The required packages have been imported");
      ArrayList<String> input_list = new ArrayList<>();
      input_list.add("Java");
      input_list.add("Python");
      input_list.add("Scala");
      input_list.add("Mysql");
      input_list.add("Redshift");
      print(input_list);
   }
}

Output

The required packages have been imported

The list is defined as:
Java Python Scala Mysql Redshift

Example 2

Here, we encapsulate the operations into functions exhibiting object oriented programming.

import java.util.ArrayList;
public class Demo {
   public static void print(ArrayList<Integer> input_list) {
      System.out.print("\nThe list is defined as:\n ");
      for(Integer elements : input_list) {
         System.out.print(elements + " ");
      }
   }
   public static void main(String[] args) {
      System.out.println("The required packages have been imported");
      ArrayList<Integer> input_list = new ArrayList<>();
      input_list.add(500);
      input_list.add(600);
      input_list.add(700);
      input_list.add(800);
      input_list.add(950);
      print(input_list);
   }
}

Output

The required packages have been imported
The list is defined as:
500 600 700 800 950