How to Create an ArrayList and Add Elements to It

This example demonstrates how to create ArrayList and add new elements to it.

Example 1: Steps to Create an ArrayList and Add Elements to it in Java

To create an ArrayList and add elements to it in Java, you can follow these steps:

Import the necessary package:

import java.util.ArrayList;

Declare an ArrayList variable:

ArrayList<String> myList = new ArrayList<>();

Replace String with the desired data type if you're working with a different type of element.

Add elements to the ArrayList using the add() method:

myList.add("Element 1"); myList.add("Element 2"); myList.add("Element 3");

You can add as many elements as needed.

Access and manipulate the elements in the ArrayList:

System.out.println(myList.get(0)); // Output: Element 1 myList.set(1, "Modified Element 2");

In the example above, get(0) retrieves the element at index 0, and set(1, "Modified Element 2") modifies the element at index 1.

Here's the complete example:

import java.util.ArrayList; public class ArrayListExample { public static void main(String[] args) { ArrayList<String> myList = new ArrayList<>(); myList.add("Element 1"); myList.add("Element 2"); myList.add("Element 3"); System.out.println(myList.get(0)); // Output: Element 1 myList.set(1, "Modified Element 2"); System.out.println(myList.get(1)); // Output: Modified Element 2 } }

Note: Remember to specify the correct data type when declaring the ArrayList, based on the type of elements you want to store.

Example 2: Create an ArrayList and Adding New Elements to It

  • How to create an ArrayList using the ArrayList() constructor.
  • Add new elements to an ArrayList using the add() method.
import java.util.ArrayList; import java.util.List; public class CreateArrayListExample { public static void main(String[] args) { // Creating an ArrayList of String List<String> animals = new ArrayList<>(); // Adding new elements to the ArrayList animals.add("Lion"); animals.add("Tiger"); animals.add("Cat"); animals.add("Dog"); System.out.println(animals); // Adding an element at a particular index in an ArrayList animals.add(2, "Elephant"); System.out.println(animals); } }

Output

[Lion, Tiger, Cat, Dog] [Lion, Tiger, Elephant, Cat, Dog]

Reference

Java ArrayList Source Code Examples


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