Multiple inheritance using interfaces in Java - Mini Project: Build & Apply

Multiple inheritance using interfaces

📖 Scenario: Imagine you are building a simple system for a smart home. Different devices can perform different actions. Some devices can turn on lights, others can play music, and some can do both.

🎯 Goal: You will create two interfaces, LightControl and MusicControl, each with one method. Then, you will create a class SmartDevice that inherits from both interfaces and implements their methods. Finally, you will create an object of SmartDevice and call both methods.

📋 What You'll Learn

Create an interface called LightControl with a method turnOnLight().

Create an interface called MusicControl with a method playMusic().

Create a class called SmartDevice that implements both LightControl and MusicControl.

Implement the methods turnOnLight() and playMusic() in SmartDevice.

Create a main method to create an object of SmartDevice and call both methods.

💡 Why This Matters

🌍 Real World

Smart home devices often need to perform multiple actions. Using interfaces allows devices to inherit multiple behaviors cleanly.

💼 Career

Understanding multiple inheritance with interfaces is important for designing flexible and reusable code in Java, a common skill in software development jobs.

1

Create interfaces for light and music control

Create an interface called LightControl with a method void turnOnLight(). Also create an interface called MusicControl with a method void playMusic().

Java

// Your code here

Need a hint?

Use the interface keyword to create interfaces. Define methods without a body.

2

Create SmartDevice class implementing both interfaces

Create a class called SmartDevice that implements both LightControl and MusicControl interfaces.

Java

interface LightControl {
    void turnOnLight();
}

interface MusicControl {
    void playMusic();
}

// Your code here

Need a hint?

Use implements keyword to inherit from interfaces. Separate multiple interfaces with commas.

3

Implement methods in SmartDevice

Inside the SmartDevice class, implement the methods turnOnLight() and playMusic(). Make turnOnLight() print "Light is turned on" and playMusic() print "Music is playing".

Java

interface LightControl {
    void turnOnLight();
}

interface MusicControl {
    void playMusic();
}

class SmartDevice implements LightControl, MusicControl {
    // Your code here
}

Need a hint?

Remember to add public before method names when implementing interface methods.

4

Create main method and test SmartDevice

Create a public static void main(String[] args) method inside a class called Main. Inside it, create an object of SmartDevice called device. Call device.turnOnLight() and device.playMusic().

Java

interface LightControl {
    void turnOnLight();
}

interface MusicControl {
    void playMusic();
}

class SmartDevice implements LightControl, MusicControl {
    public void turnOnLight() {
        System.out.println("Light is turned on");
    }
    public void playMusic() {
        System.out.println("Music is playing");
    }
}

// Your code here

Need a hint?

Make sure to create the Main class with the main method. Then create the SmartDevice object and call both methods.