Data hiding in Java - Mini Project: Build & Apply

Data hiding

📖 Scenario: You are creating a simple Java program to store and protect a person's private information, like their name and age. You want to make sure this information cannot be changed directly from outside the class.

🎯 Goal: Build a Java class that hides its data using private variables and provides public methods to access and update the data safely.

📋 What You'll Learn

Create a class called Person with private variables name and age

Add public getter methods getName() and getAge() to access the private variables

Add public setter methods setName(String name) and setAge(int age) to update the private variables

Use the setter methods to update the data and getter methods to print the data

💡 Why This Matters

🌍 Real World

Data hiding is used in real applications to protect sensitive information and control how data is accessed or changed.

💼 Career

Understanding data hiding is essential for writing secure and maintainable code in software development jobs.

1

Create the Person class with private variables

Create a class called Person with two private variables: String name and int age.

Java

public class Person {
    // Your code here
}

Need a hint?

Use the private keyword before the variable types to hide them.

2

Add public getter methods

Add two public methods: getName() that returns name and getAge() that returns age.

Java

public class Person {
    private String name;
    private int age;

    // Your code here
}

Need a hint?

Getter methods return the value of the private variables.

3

Add public setter methods

Add two public methods: setName(String name) to set the name variable and setAge(int age) to set the age variable.

Java

public class Person {
    private String name;
    private int age;

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    // Your code here
}

Need a hint?

Setter methods update the private variables using this keyword.

4

Create a main method to test data hiding

Create a Main class with a main method. Inside it, create a Person object, use setName("Alice") and setAge(30) to set data, then print the name and age using getName() and getAge().

Java

public class Person {
    private String name;
    private int age;

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

public class Main {
    public static void main(String[] args) {
        // Your code here
    }
}

Need a hint?

Create a Person object, set the name and age, then print them using the getter methods.