CNI vs interfaces

[Mo DeJong]

>Nor is this something you can do in Java.
> -- 
>        --Per Bothner
>per@bothner.com   http://www.bothner.com/~per/


On Thu, 3 Aug 2000, Bryce McKinlay wrote:
> 
> Huh? As far as I know, this is not something you can do with Java either. Or
> do I misunderstand your example?
> 
> regards
> 
>   [ bryce ]


Huh. I could have sworn that worked. Now I am
wondering why I thought that. I ran this example
and got a runtime cast exception.

interface I1 {
  void foo();
}

interface I2 {
  void foo();
}

public class ICast implements I2 {
  public void foo() { System.out.println("Called ICast.foo"); }

  public static void main(String[] args) {
    I2 itwo = new ICast();
    call( (I1) itwo );
  }

  static void call(I1 ione) {
    ione.foo();
  }
}

% java ICast
Exception in thread "main" java.lang.ClassCastException: ICast

Is runtime casting to a compatible interface something that
is supported in JDK 1.3? I could have sworn I read about
something like this somewhere, perhaps I am just confused.

Mo DeJong
Red Hat Inc