Inheritance

1// Parent class
2public class Vehicle {
3    protected String brand;
4    protected String model;
5    protected int year;
6    
7    public Vehicle(String brand, String model, int year) {
8        this.brand = brand;
9        this.model = model;
10        this.year = year;
11    }
12    
13    public void start() {
14        System.out.println("Vehicle is starting...");
15    }
16    
17    public void stop() {
18        System.out.println("Vehicle is stopping...");
19    }
20    
21    public void displayInfo() {
22        System.out.println(year + " " + brand + " " + model);
23    }
24}
25
26// Child class
27public class Car extends Vehicle {
28    private int numDoors;
29    private String fuelType;
30    
31    public Car(String brand, String model, int year, int numDoors, String fuelType) {
32        super(brand, model, year); // Call parent constructor
33        this.numDoors = numDoors;
34        this.fuelType = fuelType;
35    }
36    
37    // Method overriding
38    @Override
39    public void start() {
40        System.out.println("Car engine is starting... Vroom!");
41    }
42    
43    // Child-specific method
44    public void openTrunk() {
45        System.out.println("Trunk is now open");
46    }
47    
48    @Override
49    public void displayInfo() {
50        super.displayInfo(); // Call parent method
51        System.out.println("Doors: " + numDoors + ", Fuel: " + fuelType);
52    }
53}
54
55// Another child class
56public class Motorcycle extends Vehicle {
57    private boolean hasSidecar;
58    
59    public Motorcycle(String brand, String model, int year, boolean hasSidecar) {
60        super(brand, model, year);
61        this.hasSidecar = hasSidecar;
62    }
63    
64    @Override
65    public void start() {
66        System.out.println("Motorcycle engine roaring!");
67    }
68    
69    public void wheelie() {
70        System.out.println("Doing a wheelie!");
71    }
72}
73
74// Usage
75public class Main {
76    public static void main(String[] args) {
77        Vehicle car = new Car("Toyota", "Camry", 2024, 4, "Hybrid");
78        Vehicle bike = new Motorcycle("Harley", "Sportster", 2024, false);
79        
80        car.start();   // Car engine is starting... Vroom!
81        bike.start();  // Motorcycle engine roaring!
82        
83        car.displayInfo();  // Shows car info with doors and fuel
84    }
85}