[concurrency-interest] @Contended (JEP-142)

Vitaly Davidovich vitalyd at gmail.com
Fri Nov 30 08:36:31 EST 2012


What's the plan for making this info available in heap dumps (taken using
jmap)? I'd imagine tools like Eclipse MAT may want to indicate that a given
instance of a class has padding applied.  Otherwise, the object size
reported won't match expectation (without knowing that padding was applied).

Sent from my phone
On Nov 30, 2012 8:22 AM, "oleksandr otenko" <oleksandr.otenko at oracle.com>
wrote:

>  I think the layout monitoring tools will be none the wiser even if they
> know which fields were annotated. After all, it is only a hint, and not a
> directive on how exactly to lay out the fields.
>
> In other words, I see no reason to expose this annotation to runtime
> tools. If JVM wants to expose something useful about the actual object
> layout, it probably won't be annotations.
>
> Alex
>
> On 30/11/2012 10:07, Aleksey Shipilev wrote:
>
> On 11/30/2012 03:42 AM, oleksandr otenko wrote:
>
>  Does it need to have Retention policy = RUNTIME?
>
>
> That's an interesting point, and that is probably solves the compability
> problems, as Remi said, because you will not be able to kick off
> NoSuchClassException while traversing annotations.
>
> The downside is that (layout) monitoring tools might want to detect the
> annotation at runtime, if that is not a concern, I'm OK with making it
> CLASS.
>
> -Aleksey.
>
>
>
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