RFR: 8305186: Reference.waitForReferenceProcessing should be more accessible to tests [v5]

[Kim Barrett]

On Fri, 11 Apr 2025 23:26:45 GMT, Brent Christian <bchristi at openjdk.org> wrote:

>> test/lib/jdk/test/whitebox/WhiteBox.java line 568:
>> 
>>> 566:   private Method getWaitForReferenceProcessingMethod() {
>>> 567:     Method wfrp = waitForReferenceProcessingMethod;
>>> 568:     if (wfrp == null) {
>> 
>> Racy initialization is fine, the field can be static and the last one (any racy init would all the same) wins:
>> Suggestion:
>> 
>>   private static Method waitForReferenceProcessingMethod = getWaitForReferenceProcessingMethod();
>> 
>>   private static Method getWaitForReferenceProcessingMethod() {
>
> I can make the `Method` static, but I don't think it should be set until there's a call to `getWaitForReferenceProcessing()`, as most uses of `WhiteBox` won't need it.

Not only will most uses of `WhiteBox` not need it, but those uses would be "broken" because they would
be forced to (without benefit) add the `@modules` declaration needed to allow that to work.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24527#discussion_r2040569359