Why the class can't be cast ?

Question

class c1 {
c1 () {
System.out.println ("c1 con");
}
static void m () {
System.out.println ("m of c1");
}
}
class c2 extends c1 {
c2 () {
System.out.println ("c2 con");
}
static void m () {
System.out.println ("m of c2");
}
public static void main(String[] args) {
c1 obj=new c1 ();
((c2)obj).m();
}
}

Answer 1

Because c2 is a subclass. You can only cast to a superclass.
Suppose we have 2 classes:
class Animal {...}
class Dog extends Animal {...}
If you cast Dog to an Animal, it's ok, because every dog is an animal and it can act like animal.
But if you try to cast an Animal to a Dog, it makes no sense, because not every animal is a dog. It leads to undesirable consequences, for example a cat might start barking.

Answer 2

In addition to Stepperwolf's answer:
Sometimes you can downcast your variables to their original types like this:
c1 obj = new c2();
((c2) obj).m();
This anti-pattern can be used when you want to do some specific to type actions in polymorphic system

Answer 3

ok thank you guys..just because i ve seen a lesson about downcasting so i tried to do it

Answer 4

The Green keep trying

Answer 5

Steppenwolf, beautifully said!