Java ArrayList size()

import java.util.ArrayList;

class Main {
  public static void main(String[] args) {
    // create an ArrayList
    ArrayList<Integer> primeNumbers = new ArrayList<>();
    primeNumbers.add(2);
    primeNumbers.add(3);
    primeNumbers.add(5);
    primeNumbers.add(7);
    System.out.println("ArrayList: " + primeNumbers);

    // get the number of elements of arraylist
    int size = primeNumbers.size();
    System.out.println("Length of ArrayList: " + size);

  }
}

// Output: ArrayList: [2, 3, 5, 7]
//         Length of ArrayList: 4

Syntax of ArrayList size()

The syntax of the size() method is:

arraylist.size()

Here, arraylist is an object of the ArrayList class.

size() Parameters

The size() method does not take any parameters.

size() Return Value

• returns the number of elements present in the arraylist.

Example: Get the Length of an ArrayList

import java.util.ArrayList;

class Main {
    public static void main(String[] args) {
        // create an ArrayList
        ArrayList<String> languages = new ArrayList<>();

        // insert element to the arraylist
        languages.add("JavaScript");
        languages.add("Java");
        languages.add("Python");
        System.out.println("ArrayList: " + languages);

        // get the number of elements of arraylist
        int size = languages.size();
        System.out.println("Length of ArrayList: " + size);

    }
}

Output

ArrayList: [JavaScript, Java, Python]
Length of ArrayList: 3

In the above example, we have created an arraylist named languages. Here, we have used the size() method to get the number of elements present in the arraylist.

Also Read:

• Java HashMap size()