Protected access modifier in Java - Mini Project: Build & Apply

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Understanding the Protected Access Modifier in Java

📖 Scenario: Imagine you are creating a simple program with two classes: a parent class and a child class. You want to share some information between these classes but keep it hidden from other unrelated classes.

🎯 Goal: Build a Java program that shows how the protected access modifier allows a child class to access a variable from its parent class, but keeps it hidden from other classes.

📋 What You'll Learn

Create a parent class called Parent with a protected integer variable named number set to 10.

Create a child class called Child that extends Parent.

In the Child class, write a method called showNumber that returns the value of number.

Create a separate class called Main with a main method to create an object of Child and print the value returned by showNumber.

💡 Why This Matters

🌍 Real World

In real software, <code>protected</code> helps keep important data safe but still accessible to related parts of the program.

💼 Career

Understanding access modifiers like <code>protected</code> is essential for writing secure and well-structured Java code in professional development.

1

Create the Parent class with a protected variable

Create a class called Parent with a protected integer variable named number and set it to 10.

Java

class Parent {
    // Your code here
}

💡 Need a hint?

Use the keyword protected before the variable type to allow child classes to access it.

2

Create the Child class that extends Parent

Create a class called Child that extends the Parent class.

Java

class Parent {
    protected int number = 10;
}

// Your code here

💡 Need a hint?

Use the keyword extends to make Child inherit from Parent.

3

Add a method in Child to access the protected variable

In the Child class, add a method called showNumber that returns the value of the protected variable number.

Java

class Parent {
    protected int number = 10;
}

class Child extends Parent {
    // Your code here
}

💡 Need a hint?

Since number is protected, you can access it directly inside Child.

4

Create Main class to test access to protected variable

Create a class called Main with a main method. Inside main, create an object of Child and print the value returned by showNumber.

Java

class Parent {
    protected int number = 10;
}

class Child extends Parent {
    public int showNumber() {
        return number;
    }
}

// Your code here

💡 Need a hint?

Use System.out.println to print the value returned by showNumber.