On Tue, 21 Jan 2025 18:44:39 GMT, Justin Lu <j...@openjdk.org> wrote:
>> src/java.base/share/classes/java/util/Currency.java line 469:
>>
>>> 467:
>>> 468: // Initialize the set of available currencies if needed
>>> 469: private static synchronized void initAvailableCurrencies() {
>>
>> Should we make `available` volatile so we can avoid entering the monitor if
>> the currencies are initialized?
>>
>> (Note: We may get Stable Values very soon, at that point SV is a much better
>> solution)
>
> Thanks Chen, made `available` volatile and implemented DCL in
> https://github.com/openjdk/jdk/pull/23165/commits/96e86c800f1d1af1c20bfee944c298f17b7e8860.
> Also added a duplicate elements test as you suggested.
I'm not sure how useful it is to optimize the performance of
`availableCurrencies` access to "available", but adding volatile will slow
every access down.
The computation of the available currencies is stable, so a race computing it
is benign.
Except for the available hashSet being partially filled when read by the thread
calling `getAvailableCurrencies()`.
That could be remedied by using a new local for the new HashSet in
initAvailableCurrencies and assigning to available only when the set is
completely initialized.
(And yes, this looks like a good fit for stable values.)
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/23165#discussion_r1925680680
