Type casting class example in java (generalization and specialization example in java)

public class First {

public static void main(String[] args) {
// TODO Auto-generated method stub
Second obj =  new Third();
obj.s();
Third obj1 = new Four();
obj1.s();
obj1.T();
Second obj2 = new Four();
obj2.s();
Second obj3 = new Third();
Third obj4 = (Third) obj3;
obj4.s();
obj4.T();
}
}


public class Second {
void s(){
System.out.println("Parent Second");
}

}


class Third extends Second{

void T(){

System.out.println("Parent Third");
}

}

class Four extends Third{
void F(){

System.out.println("Parent Four");
}
}

output:-
Parent Second
Parent Second
Parent Third
Parent Second
Parent Second
Parent Third