Odd compiler behavior with annotations

Question

Hi all,
I apologize if this is the wrong forum, but the JDev code editor behavior is a significant part of this. I have an annotation type, TestParameters. If I write the following line:
TestParameters params = (TestParameters) someClass.getAnnotation(TestParameters.class);then the cast is greyed out in the code editor, and code assistance tells me it's unnecessary. Since the signature of getAnnotation is
<A extends Annotation> A getAnnotation(Class<A>)this is what I'd expect; I really shouldn't need that cast.
However, if I take the cast out, although nothing is marked red in the code editor, I get a compiler error:
Error(32,29): incompatible types; found: interface java.lang.annotation.Annotation,
required: annotation annotation.TestParametersWhat's going on here? I'm 95% sure the code should compile without the cast.
Thanks much,
Avrom

Answer 1

Aha! You're right, what it prints out is not what I'd expected:
class $Proxy3I was using ojc, but javac gives the same results (including the compiler error: "incompatible types").
Not entirely sure what's going on here...either the Javadoc for Class.getAnnotation() and the JDev code assistance is both wrong, or something odder is going on.
Message was edited by:
Avrom
ha! Found the issue.
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5104826
(This was closed by Sun as not a bug.)
The problem was that someClass was declared as type Class, rather than Class<?>. I guess my understanding of generics wasn't quite up to snuff; I'd been assuming that the declarations
SomeType myObj;and
someType<?> myObj;were identical, since you can't access the wildcard in the class containing myObj, but apparently the compiler doesn't see them that way. My bad.