final being overridden??

[sonir shah]

class Base{
public final void amethod(){
        System.out.println("amethod");
        }
}
public class Fin extends Base{
public static void main(String argv[]){
        Base b = new Base();
        b.amethod();
        }
}

Ans: It will compile and give the output "amethod" when run
I feel the answer is wronf becauase once a method declared final cannot be used in the subclass..am i right?
By the way, can private methods be called in the sub classes??
Sonir

[William Brogden]

The b.amethod() call is to the method in Base. Even if the code was:
Fin f = new Fin();
f.amethod();
It would be to the inherited method from Base. What you can't do is override amethod with a new definition in Fin.
Bill
[ January 10, 2002: Message edited by: William Brogden ]

[Corey McGlone]

The keyword final, when used with a method, simply means that the method cannot be over-ridden. In this case, the method is being inherited, not over-ridden. The following code, however, would be illegal:

class Base
{
   public final void amethod()
   {
      System.out.println("amethod");
   }
}
public class Fin extends Base
{
   public static void main(String argv[])
   {
      amethod();
   }
   // Illegal - Cannot override a final method
   public void amethod()
   {
      System.out.println("Class Fin's amethod");
   }
}

However, the following code is perfectly legal because it utilized an inherited method (which can be final).

class Base
{
   public final void amethod()
   {
      System.out.println("amethod");
   }
}
public class Fin extends Base
{
   public static void main(String argv[])
   {
      // Legal - we're just calling an inherited method
      amethod();
   }
}

I hope this makes sense, but the key is that the keyword final means that you can't over-ride a method, not that you can't use it in a child class (that's what the private access modifier is for).
Corey

[sonir shah]

Hi Corey..
I guess both the methods example which u gave are very similar
I cannot understand the differnce between the 2.
Still u have said that one of them is legal while the other one is not.
Can u give me some explainations?
Sonir

[Jason Kretzer]

Sonir,
Notice that in his second example he did not try to define amethod in the subclass as this is what is illegal. You cannot override(or redefine) a final method that was defined in the super class.

HTH,

[Corey McGlone]

Originally posted by Jason Kretzer:
Sonir,
Notice that in his second example he did not try to define amethod in the subclass as this is what is illegal. You cannot override(or redefine) a final method that was defined in the super class.

HTH,

Jason is right - it's the declaration of amethod in the subclass that is illegal - not the call to that method. If this is still confusing, please let me know and I'll try to elaborate.
Corey