RFR: 8352565: Add native method implementation of Reference.get() [v2]

[Kim Barrett]

On Tue, 1 Apr 2025 22:01:55 GMT, Brent Christian <bchristi at openjdk.org> wrote:

>> Kim Barrett has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   parameterized return type of native get0
>
> test/hotspot/jtreg/gc/TestNativeReferenceGet.java line 162:
> 
>> 160:         System.out.println("Testing nonconcurrent GC");
>> 161:         clearReferents();
>> 162:         strengthenReferents();
> 
> Might the GC clear refs between `clearReferents()` and `strengthenReferents()`?

Yeah, an ill-timed GC between those operations would result in test failure.
I've added a GC immediately before those operations to make that pretty unlikely.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24315#discussion_r2025385681