Unboxing in Java - Mini Project: Build & Apply

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Unboxing

📖 Scenario: Imagine you have a box that holds a number, but the number is wrapped inside an object. You want to take the number out of the box to use it as a simple number in your program.

🎯 Goal: You will learn how to convert a wrapped number (an Integer object) into a simple number (int) using unboxing in Java.

📋 What You'll Learn

Create an Integer object with a specific value

Create an int variable to hold the unboxed value

Use unboxing to convert the Integer object to int

Print the unboxed int value

💡 Why This Matters

🌍 Real World

Unboxing is useful when you receive numbers as objects but need to use them as simple numbers for calculations or comparisons.

💼 Career

Understanding unboxing helps in writing efficient Java code, especially when working with collections or APIs that use wrapper classes.

1

Create an Integer object

Create an Integer object called boxedNumber and set it to 100.

Java

// Your code here

💡 Need a hint?

Use Integer boxedNumber = 100; to create the object.

2

Create an int variable for unboxing

Create an int variable called unboxedNumber to hold the unboxed value from boxedNumber.

Java

public class Main {
    public static void main(String[] args) {
        Integer boxedNumber = 100;
        // Your code here
    }
}

💡 Need a hint?

Assign boxedNumber directly to unboxedNumber to unbox.

3

Use unboxed value in a calculation

Add 50 to unboxedNumber and store the result in a new int variable called result.

Java

public class Main {
    public static void main(String[] args) {
        Integer boxedNumber = 100;
        int unboxedNumber = boxedNumber;
        // Your code here
    }
}

💡 Need a hint?

Use int result = unboxedNumber + 50; to add 50.

4

Print the result

Print the value of result using System.out.println.

Java

public class Main {
    public static void main(String[] args) {
        Integer boxedNumber = 100;
        int unboxedNumber = boxedNumber;
        int result = unboxedNumber + 50;
        // Your code here
    }
}

💡 Need a hint?

Use System.out.println(result); to display the number.