ArrayList clear() Method in Java with Examples

Last Updated : 10 Dec, 2024

The clear() method in the ArrayList class in Java is used to remove all elements from an ArrayList. After calling this method, the list becomes empty.

Example 1: Here, we will use the clear() method to clear elements from an ArrayList of Integers.

// Java program to demonstrate clear() method
// in Integer ArrayList
import java.util.ArrayList;

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

        // Creating an ArrayList of integers
        ArrayList<Integer> n = new ArrayList<>();

        // Adding elements to the ArrayList
        n.add(10);
        n.add(20);
        n.add(30);

        // Printing the original ArrayList
        System.out.println("" + n);

        // Clearing all elements from the ArrayList
        n.clear();

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

Output

[10, 20, 30]
[]

Syntax of clear() Method

public void clear()

Parameter: The 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.

Important Point: It does implement interfaces like Serializable, Cloneable, Iterable, Collection, List, RandomAccess.

Example 2: Here, we will use the clear() method to clear elements from an ArrayList of Strings.

// Java program to demonstrate clear() method
// in ArrayList of Strings
import java.util.ArrayList;

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

        // Creating an ArrayList of strings
        ArrayList<String> a = new ArrayList<>();

        // Adding elements to the ArrayList
        a.add("Dog");
        a.add("Cat");
        a.add("Rabbit");

        // Printing the original ArrayList
        System.out.println("" + a);

        // Clearing all elements 
        // from the ArrayList
        a.clear();

        // Printing the ArrayList after clearing
        System.out.println("" + a);
    }
}

Output

[Dog, Cat, Rabbit]
[]

Example 3: Here, we will use the clear() method to clear elements from an ArrayList of Objects.

// Java program to demonstrate clear() method
// in ArrayList of Objects
import java.util.ArrayList;

public class GFG {
  
    static class Person {
        String n;
        
        Person(String n) {
            this.n = n;
        }
        
        public String toString() {
            return n;
        }
    }

    public static void main(String[] args) {
      
        // Create ArrayList of Person objects
        ArrayList<Person> p = new ArrayList<>();
        
        // Add objects
        p.add(new Person("Ram"));
        p.add(new Person("Shyam"));
        
        // Print before clearing
        System.out.println("" + p);
        
        // Clear the ArrayList
        p.clear();
        
        // Print after clearing
        System.out.println("" + p);
    }
}