ArrayList size() Method in Java with Examples

Last Updated : 10 Dec, 2024

In Java, the size() method is used to get the number of elements in an ArrayList.

Example 1: Here, we will use the size() method to get the number of elements in an ArrayList of integers.

// Java program to demonstrate the use of 
// size() method for 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(21);
        n.add(22);
        n.add(23);

        // Getting and printing the 
        // size of the ArrayList
        int s = n.size();
        System.out.println("" + s);
    }
}

Output

Syntax of ArrayList `size()` Method

public int size()

Returns Value: This method returns the number of elements in the list.

Example 2: Here, we use the size() method to get the number of elements in an ArrayList of strings.

// Java program to demonstrate the use of 
// size() method for String ArrayList
import java.util.ArrayList;

public class GFG {
    public static void main(String[] args) {
      
        // Creating an ArrayList of Strings
        ArrayList<String> f = new ArrayList<>();

        // Adding elements to the ArrayList
        f.add("Apple");
        f.add("Banana");
        f.add("Orange");

        // Getting and printing the 
        // size of the ArrayList
        int s = f.size();
        System.out.println("" + s);
    }
}

Output

Example 3: Here, we demonstrate how to use the size() method on an ArrayList that stores objects.

// Java program to demonstrate the use of 
// size() method for Object ArrayList
import java.util.ArrayList;

class Person {
    String n;
    int a;

    Person(String n, int a) {
        this.n = n;
        this.a = a;
    }
}

public class Main {
    public static void main(String[] args) {
      
        // Creating an ArrayList of Person objects
        ArrayList<Person> p = new ArrayList<>();

        // Adding elements (objects) to the ArrayList
        p.add(new Person("Ram", 22));
        p.add(new Person("Shyam", 25));

        // Getting and printing the 
        // size of the ArrayList
        int s = p.size();
        System.out.println("" + s);
    }
}