Public methods with package-only access?!

Question

Hello,
I've just encountered the following problem:
I was trying to invoke a method from the interface java.util.List via reflection on an instanceo obtained via java.util.Arrays.asList(Object[] array).
Although this method is public (since is is declared in a public interface), the invocation failed with an IllegalAccessException.
I guess the reckoning behind this is that the entire class has package protected access, thus you may not access any member reflectively outside its package.
Does this really make sense? Is there a way to circumvent this behaviour?
Any thoughts appreciated!

Answer 1

I doubt your assumption (package protected) because
asList simple returns an ArrayList. And if in an
interface a method is declared you cannot reduce it's
visibilty in an implementing class.Yes, the methods are all declared public, but the entire class (java.util.Arrays.ArrayList) is package-protected.
But still, it's strange: you can obtein the method using, for instance, Arrays.asList(new Object[]{"hallo"})getClass().getMethod("size", null), but you cannot invoke it! Ironically, the error message of the IllegalAccessException says "cannot access member with modifiers public"...
>
But you can set the method accesible for reflection
calls through:
Method.setAccessible(true)
Ah, thanks, now it works!
But isn't that kinda dirty? If there was a Security Manager present, it would immediately fail, wouldn't it?
I'd still like to understand why you cannot simply invoke a public method of a package-protected class!