RFR: 8331008: Implement JEP 478: Key Derivation Function API (Preview) [v10]

[Kevin Driver]

On Thu, 5 Sep 2024 15:50:42 GMT, Viktor Klang <vklang at openjdk.org> wrote:

>> Well, I am not so sure, I've sent you pointers separately regarding lazy initialization and the relevant concurrency pointers.
>
> I'd recommend documenting above this line what function the lock is intending to serve, and by each of the members that it guards accesses to. Something like "//guarded by 'lock'".
> 
> Also, ook into whether the members guarded by the lock needs `volatile`: http://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html

My understanding is that `volatile` is used when accessing the contents of the object, which we are not doing with this locking object, so IMO there is no reason for the keyword to be added.

I'll apply your other suggestion about explicit comments.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20301#discussion_r1745944991