ClassCastException ??

[Bram Maes]

Hello fellow ranchers,

I was busy experimenting a bit the protected access modifier when using inheritance. When I run the following I get a ClassCastException and I don't know why.... Can anyone help me ?
Thanks.


SuperClass.java :

   
package myPackage1;
 
public class SuperClass {

protected int a = 4;
 
protected int getA() {
return a;
}
 
protected void setA(int a) {
this.a = a;
}

}

SubClass.java :

  
package myPackage2;
 
import myPackage1.*;
 
public class SubClass extends SuperClass {
 
public static void main(String[] args) {
SuperClass s = new SuperClass();
SubClass sc = (SubClass) s;
sc.setA(3);
 
}
 
}

[Petrus Pelser]

Originally posted by Bram Maes:

  
SuperClass s = new SuperClass();
SubClass sc = (SubClass) s;

You can't cast an object of a superclass to the type of a subclass.

The following would be fine:

SuperClass s = new SubClass();
SubClass sc = (SubClass) s;

[Bram Maes]

Stupid mistake... you're right

thanks a lot!

[Joe Harry]

Hi above,

You are casting down the inheritance tree. You will only be able to make it pass the compiler but it melts down at run time.

Regards,
Jothi Shankar Kumar. S