RFR: 8288327: Executable.hasRealParameterData should not be volatile [v2]

[ExE Boss]

On Mon, 13 Jun 2022 19:55:47 GMT, Сергей Цыпанов <duke at openjdk.org> wrote:

>> If there are two threads calling `Executable.hasRealParameterData()` under race and the first one writes into volatile `Executable.parameters` field (doing _releasing store_) and the second thread reads non-null value from the same field (doing acquiring read) then it must read exactly the same value written into `hasRealParameterData` within `privateGetParameters()`. The reason for this is that we assign `hasRealParameterData` before  _releasing store_.
>> 
>> In the opposite case (_acquiring read_ reads null) the second thread writes the value itself and returns it from the method so there is no change in behavior.
>
> Сергей Цыпанов has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8288327: Add clarifying comments

src/java.base/share/classes/java/lang/reflect/Executable.java line 453:

> 451: 
> 452:     private transient boolean hasRealParameterData;
> 453:     private transient volatile Parameter[] parameters;

These can probably be annotated with `@Stable` (see also [GH‑8742]):
Suggestion:

    private transient @Stable boolean hasRealParameterData;
    private transient @Stable volatile Parameter[] parameters;


[GH‑8742]: https://urldefense.com/v3/__https://github.com/openjdk/jdk/pull/8742__;!!ACWV5N9M2RV99hQ!Pu7IhhN7O8BZ8UFonTLx3XeO8PLqruZTKko5qqtlFfXoeqkvrnO5pNA5lvtjZOVqSVk2yzbMa5S8nkxjwuO1$ 

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PR: https://git.openjdk.org/jdk/pull/9143