What is Inheritance and how does it work in Java? Java में Inheritance क्या है और यह कैसे काम करता है?

Inheritance is a mechanism where a child class inherits properties and methods from a parent class. It promotes code reusability and establishes a relationship between classes.

// Parent Class
public class Vehicle {
    protected String color;
    protected int speed;
    
    public void start() {
        System.out.println('Vehicle started');
    }
    
    public void stop() {
        System.out.println('Vehicle stopped');
    }
}

// Child Class (inherits from Vehicle)
public class Car extends Vehicle {
    private int numberOfDoors;
    
    public Car(String color, int speed, int doors) {
        this.color = color;
        this.speed = speed;
        this.numberOfDoors = doors;
    }
    
    // Overriding parent method
    @Override
    public void start() {
        System.out.println('Car engine started');
    }
    
    public void displayDoors() {
        System.out.println('Number of doors: ' + numberOfDoors);
    }
}

// Another Child Class
public class Bike extends Vehicle {
    private boolean hasHelmet;
    
    public void wheelie() {
        System.out.println('Bike doing wheelie');
    }
}

// Using Inheritance
public class Main {
    public static void main(String[] args) {
        Car car = new Car('Red', 100, 4);
        car.start();           // Calls overridden method
        car.displayDoors();
        
        Bike bike = new Bike();
        bike.start();          // Calls parent method
        bike.wheelie();
    }
}

// Types of Inheritance:
// 1. Single Inheritance: Child extends one Parent
// 2. Multilevel Inheritance: A extends B, B extends C
// 3. Hierarchical Inheritance: Multiple children extend one parent
// 4. Multiple Inheritance: Not directly supported (use interfaces)