Cast.java

class Cast {
    public static void main(String[] args) {

        Object obj = "abcd";
        String str = (String) obj;

        Object obj2 = new Integer(10);
        // java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String
        ///String str2 = (String) obj2;

        Object obj3 = new Object();
        // java.lang.Object cannot be cast to java.lang.String
        ///String str3 = (String) obj3;

        Car myCar = new SportCar();
        SportCar myCar2 = (SportCar) myCar;
        // java.lang.ClassCastException: SportCar cannot be cast to Truck
        /// Truck myCar3 = (Truck) myCar;
    }
}

class Car {
    protected int speedMax = 100;
    private long id;


    public Car(long id, int speedMax) {
        this.id = id;
        this.speedMax = speedMax;
    }

    public Car() {

    }

    @Override
    public int hashCode() {
        int result = (int) (id ^ (id >>> 32));
        result = 31 * result + speedMax;
        return result;
    }

    @Override
    public boolean equals(Object o)  {
        if(this == o) return true;
        if(o == null || getClass() != o.getClass()) return false;
        Car car = (Car) o;
        if(id != car.id) return false;
        return true;
    }
    public int getSpeedMax() {
        return speedMax;
    }

    @Override
    public String toString() {
        return "My name is car.";
    }

    public Car getNewCar() {
        return new Car();
    }

    public void move() {
        System.out.println("Car move.");
    }
}

class Truck extends Car {
    @Override
    public void move() {
        System.out.println("Truck move.");
    }
}

class SportCar extends Car {
    protected int speedMax = 300;

    public SportCar(long id, int speedMax) {
        super(id, speedMax);
    }

    public SportCar() {

    }

    public int getSpeedMax() {
        return speedMax;
    }

    @Override
    public String toString() {
        return super.toString() + "Sport car.";
    }

    public void testSuper() {
        System.out.println(super.speedMax);
        System.out.println(this.speedMax);
    }

    @Override
    public SportCar getNewCar() {
        return new SportCar();
    }

    @Override
    public void move() {
        System.out.println("Sport car move.");
    }
}