upcastingAndDowncasting.java

class Machine {
    public void start() {
        System.out.println("Machine Started");
    }
}

class Camera extends Machine {
    public void start() {
        System.out.println("Camera Started");
    }

    public void snap() {
        System.out.println("Photo taken.");
    }
}

public class upcastingAndDowncasting {
    public static void main(String[] args) {
        Machine machine1 = new Machine();
        Camera camera1 = new Camera();

        machine1.start();
        camera1.start();
        camera1.snap();

        //Upcasting
        Machine machine2 = camera1;
        machine2.start();

        //error machine2.snap()

        //Downcasting
        Machine machine3 = new Camera();
        Camera camera2 = (Camera)machine3;

        camera2.start();
        camera2.snap();

        //Doesnt work -- runtime Error
        Machine machine4 = new Machine();
        // Camera camera3 = (Camera)machine4;
        // camera3.start();
        // camera3.snap();
        
    }
}