7122142 : (ann) Race condition between isAnnotationPresent and getAnnotations

[Joel Borggrén-Franck]

Hi Peter,

Thanks for the quick update!

While I have looked over the changes to j.l.Class and the cas in AnnotationType I don't think I'm qualified to review that. (FWIW it looked fine to me but my jmm isn't swapped in at the moment so I won't pretend to know the interactions between volatile and Unsafe cas). Thinking out loud I suppose we can assume a stable offset of fields in Class, and I realize that part has been under review before.

The rest of AnnotationType, AnnotationParser and the tests look fine though. I also ran the tests before and after the change and results were as expected.

Since I'm not a Reviewer kind of reviewer you need to get one those to sign off but after that I think you are good to go. I can sponsor this as well if Alan is busy.

cheers
/Joel

On 5 jul 2013, at 11:12, Peter Levart <peter.levart at gmail.com> wrote:

> Hi Again,
> 
> Sorry, the 4th revision I posted is not rebased to the current tip of jdk8-tl so it contained some diffs that reverted some things.
> 
> Here's the correct patch:
> 
> http://cr.openjdk.java.net/~plevart/jdk8-tl/AnnotationType/webrev.05/
> 
> 
> Regards, Peter
> 
> 
> On 07/05/2013 10:32 AM, Peter Levart wrote:
>> Hi Joel,
>> 
>> Here's the 4th revision of the patch:
>> 
>> http://cr.openjdk.java.net/~plevart/jdk8-tl/AnnotationType/webrev.04/
>> 
>> This one introduces CAS-ing of the AnnotationType instance into the Class.annotationType field so that there's only a single instance ever returned for a single Class. I also introduced new private static Class.Atomic nested class that is used to lazily initialize Unsafe machinery and to provide a safe wrapper for internal j.l.Class use. Previously this was part of ReflectionData nested class because it was only used for it's purpose. In anticipation to have a need for more atomic operations in the future, I moved this code to a separate class. ReflectionData is now just a record.
>> 
>> Regards, Peter
>