Java ArrayList add() Method with Examples (original) (raw)

Last Updated : 14 Mar, 2026

The add() method in Java ArrayList is used to insert elements into the list dynamically. It allows adding elements either at the end of the list or at a specific index position.

• Supports dynamic insertion of elements without needing to define the size in advance.
• Provides two forms: add(E element) and add(int index, E element). Java `

import java.util.*;

public class GFG { public static void main(String[] args) {

    // Creating an empty ArrayList
    ArrayList<Integer> al = new ArrayList<>();

    // Use add() method to 
    // add elements in the list
    al.add(10);
    al.add(20);
    al.add(30);

    System.out.println("" + al);
}

}

`

Syntax of add(Object element)

public boolean add(Object element)

• **Parameters: element: The element to be appended to the list.
• **Return Type: boolean: It returns true, if the element was successfully added.

**Example 2: add(int index, Object element)

This method inserts the specified element at a given position in the ArrayList. It shifts the current element at that position and subsequent elements to the right.

Syntax of add(int index, Object element)

void add(int index, Object element)

**Parameters:

• **index: The position at which the specified element is to be inserted.
• **element: The element to be inserted.

**Exception: Throws IndexOutOfBoundsException if the specified index is out of range (index < 0 or index > size()).

Java `

import java.util.*;

public class GFG { public static void main(String[] args) {

    // Creating an empty ArrayList
    ArrayList<Integer> al = new ArrayList<>();

    // Use add() method to 
    // add elements in the list
    al.add(10);
    al.add(20);
    al.add(30);
    al.add(40);

    System.out.println("" + al);

    // Adding new element 
    // at index 2
    int i = 2;
    al.add(i, 21);

    System.out.println("" + al);
}

}

`

Output

[10, 20, 30, 40] [10, 20, 21, 30, 40]

**Note:

• **Valid Index Range: The valid range for add(index, element) is 0 ≤ index ≤ size(). If 0 ≤ index < size(), the element is inserted at that position and existing elements shift to the right; if index = size(), the element is added at the end of the list (same as add(element)).
• **Invalid Index: If the index > size() or index < 0, Java throws an IndexOutOfBoundsException because elements cannot be inserted outside the valid list boundary.