Wrapper Classes Practice Test

In the given program, an ArrayList stores objects, so scores use Integer wrappers instead of primitive int values.

import java.util.ArrayList;

public class ScoreTracker {

    public static void main(String[] args) {

        ArrayList<Integer> scores = new ArrayList<>();

        // Wrapper objects can be stored; primitives cannot be generic types

        scores.add(11);

        scores.add(22);

        System.out.println(scores);

    }

}

What is the purpose of using wrapper classes in this scenario?

In the given program, collections store objects, so scores use wrappers not primitives.

import java.util.ArrayList;

public class ScoreTracker {

    public static void main(String[] args) {

        ArrayList<Integer> scores = new ArrayList<>();

        // Add primitive int values; autoboxing wraps them as Integer

        scores.add(10);

        scores.add(25);

        int total = scores.get(0) + scores.get(1); // unboxing for addition

        System.out.println(total);

    }

}

How does autoboxing work in the given example?