Are C#'s attributes better designed than Java's annotations?

Question

After reading this old post from Clinton Begin (creator of iBatis) I really wonder if his claims about annotations vs. attributes are widely accepted or if there is disagreement about it.

His points are:

• Annotations are not extendable
• No support for positional arguments
• Java-unlike definition syntax
• annotation is not a keyword (unlike enum)

Do those claims have merit and how does C# improve on that?

Answer 1

Well taken one by one those points obviously have merit:

• Attributes are classes you can extend and query as you wish. You can even add your own!
• Position arguments (I'm guessing you mean named arguments) are indeed possible with C#, with full Intellisense support.
• Can't really comment on how weird it looks, although coming from Razor it makes me think of macro expansion.
• Attributes don't have a keyword either, they're just a normal class.

That doesn't make Java's implementation worse, since they had a different goal in mind: backwards compatibility. C# had the advantage of building the language from scratch (and then progressing forward instead of maintaining strict backwards compatibility).

As a nit-pick though, nothing you or I mentioned are part of C#, they are part of the .NET runtime and can be found equally well in VB.NET and F#.