ArrayList clear() Method in Java with Examples

The clear() method of ArrayList in Java is used to remove all the elements from a list. The list will be empty after this call returns so whenever this operation has been performed all elements of the corresponding ArrayList will be deleted so it does it becomes an essential function for deleting elements in ArrayList from memory leading to optimization.

Syntax

public void clear()

Parameters

clear method does not need any parameters.

Return Type

It does not return any value as it removes all the elements in the list and makes it empty. 

Tip: It does implement the following interfaces as follows: Serializable, Cloneable, Iterable<E>, Collection<E>, List<E>, RandomAccess

Example of ArrayList clear() Method

Example 1:

Java

// Java Program to Illustrate Working of clear() Method
// of ArrayList class

// Importing required classes
import java.util.ArrayList;

// Main class
public class GFG {

    // Main driver method
    public static void main(String[] args)
    {
        // Creating an empty Integer ArrayList
        ArrayList<Integer> arr = new ArrayList<Integer>(4);

        // Adding elements to above ArrayList
        // using add() method
        arr.add(1);
        arr.add(2);
        arr.add(3);
        arr.add(4);

        // Printing the elements inside current ArrayList
        System.out.println("The list initially: " + arr);

        // Clearing off elements
        // using clear() method
        arr.clear();

        // Displaying ArrayList elements
        // after using clear() method
        System.out.println(
            "The list after using clear() method: " + arr);
    }
}

Output

The list initially: [1, 2, 3, 4]
The list after using clear() method: []

Example 2:

In this example, we create a new ArrayList called animals and add some elements to it using the add() method. Then, we print the elements of the ArrayList.

Next, we call the clear() method to remove all elements from the ArrayList. Finally, we print the elements of the ArrayList again to demonstrate that it is now empty.

Java

import java.util.ArrayList;

public class Main {
    public static void main(String[] args)
    {
        // Create a new ArrayList
        ArrayList<String> animals = new ArrayList<>();

        // Add some elements to the ArrayList
        animals.add("Dog");
        animals.add("Cat");
        animals.add("Rabbit");
        animals.add("Bird");

        // Print the elements of the ArrayList
        System.out.println("Animals: " + animals);

        // Clear the ArrayList using the clear() method
        animals.clear();

        // Print the elements of the ArrayList after
        // clearing it
        System.out.println("Animals after clearing: "
                           + animals);
    }
}

Output

Animals: [Dog, Cat, Rabbit, Bird]
Animals after clearing: []