RFR: 7904028: jcstress: Address s.m.Unsafe use warnings which fail build on JDK 23+ [v2]

[Aleksey Shipilev]

On Thu, 19 Jun 2025 09:06:25 GMT, Pavel Rappo <prappo at openjdk.org> wrote:

>> Here I propose a simple, symptomatic solution to fix build failures on JDK 23+ caused by treating "deprecated for removal" warnings as errors.
>> 
>> In the patch, I tried to keep the scope of `@SuppressWarnings` to a minimum. However, in a few cases I had to broaden it. This is because this annotation cannot be applied to a static initializer or an assignment within it.
>> 
>> Instead of extracting code into methods for the sake of annotating those, I annotated the smallest annotatable outer element, which was the top-level class. For example, see: `UnsafeBusyLoopTest`, `UnsafeAddLong1`, `UnsafeAddLong42`. 
>> 
>> I note that in JBS @shipilev suggested another approach to address the warnings. Namely, to move from `Unsafe` to `VarHandle`. However, such an approach is beyond my competence. And if chosen, it should be done by someone else. Thanks.
>
> Pavel Rappo has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains two commits:
> 
>  - Merge branch 'master' into CODETOOLS-7904028
>  - Initial commit

It is not very clear why sometimes we do `@SuppressWarnings` on the class, and sometimes on the fields/methods. I think doing all annotations on class-level is clean enough. Your call, though.

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Marked as reviewed by shade (Committer).

PR Review: https://git.openjdk.org/jcstress/pull/165#pullrequestreview-2942237733