Inheritance

In object-oriented design, inheritance is a mechanism that allows one class to inherit the properties and behaviors of another class. The class that inherits is called the child class or subclass, and the class being inherited from is called the parent class or superclass.

Inheritance facilitates code reuse and maintainability by allowing us to define common attributes and methods in a parent class and have them automatically available in the child class.

Let's consider the example of a Vehicle class and a Car class that inherits from it:

1class Vehicle {
2    protected String brand;
3    protected int year;
4
5    public Vehicle(String brand, int year) {
6        this.brand = brand;
7        this.year = year;
8    }
9
10    public void start() {
11        System.out.println("Starting the vehicle...");
12    }
13}
14
15class Car extends Vehicle {
16    private int numOfDoors;
17
18    public Car(String brand, int year, int numOfDoors) {
19        super(brand, year);
20        this.numOfDoors = numOfDoors;
21    }
22
23    public void drive() {
24        System.out.println("Driving the car...");
25    }
26}
27
28public class Main {
29    public static void main(String[] args) {
30        Car myCar = new Car("Toyota", 2021, 4);
31        myCar.start();
32        myCar.drive();
33    }
34}

In this example, the Vehicle class serves as the parent class, and the Car class inherits from it. The Car class extends the Vehicle class using the extends keyword.

The Vehicle class has properties such as brand and year, as well as a method start().

The Car class adds an additional property numOfDoors and a method drive(). It can also access the properties and methods defined in the Vehicle class using the super keyword.

By creating an instance of the Car class and calling its methods, we can see the inheritance in action. The output of the above code will be:

1Starting the vehicle...
2Driving the car...

In summary, inheritance allows classes to inherit properties and behaviors from other classes, facilitating code reuse and maintainability.

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}

class Vehicle {

    protected String brand;

    protected int year;

​

    public Vehicle(String brand, int year) {

        this.brand = brand;

        this.year = year;

    }

​

    public void start() {

        System.out.println("Starting the vehicle...");

    }

}

​

class Car extends Vehicle {

    private int numOfDoors;

​

    public Car(String brand, int year, int numOfDoors) {

        super(brand, year);

        this.numOfDoors = numOfDoors;

    }

​

    public void drive() {

        System.out.println("Driving the car...");

    }

}

​

class Main {

    public static void main(String[] args) {