On Thu, 9 Feb 2023 13:46:14 GMT, Per Minborg <pminb...@openjdk.org> wrote:

>> `ZoneOffset` instances are cached by the `ZoneOffset` class itself for 
>> values in the range [-18h, 18h] for each second that is on an even quarter 
>> of an hour (i.e. at most 2*18*4+1 = 145 values). 
>> 
>> Instead of using a `ConcurrentHashMap` for caching instanced, we could 
>> instead use an `AtomicReferenceArray` with direct slot value access for said 
>> even seconds. This will improve performance and reduce the number of object 
>> even though the backing array will go from an initial 32 in the CHM to an 
>> initial/final 145 in the ARA. The CHM will contain much more objects and 
>> array slots for typical numbers of entries in the cache and will compute 
>> hash/bucket/collision on the hot code path for each cache access.
>
> Per Minborg has updated the pull request incrementally with three additional 
> commits since the last revision:
> 
>  - Remove unused setup method
>  - Rename method in test
>  - Add copyright header

Other potential candidates for using `LazyReferenceArray`:

* java.nio.charset.CoderResult
* ZoneRule
* Locale
* sun.font.FileFontStrike, PhysicalStrike
* sun.security.Token
* sun.security.provider.ParameterCache
* sun.security.ssl.SSLSessionContextImpl
* sun.util.locale.provider.LocaleProviderAdapter

NOTE: The one mentioned above are candidates and further investigation is 
needed to see if they are actually a fit.

-------------

PR: https://git.openjdk.org/jdk/pull/12346

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