RFR: JDK-8274686 : java.util.UUID#hashCode() should use Long.hashCode()

[Сергей Цыпанов]

On Wed, 6 Oct 2021 09:26:06 GMT, Peter Levart <plevart at openjdk.org> wrote:

>> This is trivial fix of [JDK-8274686](https://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-8274686) which replaces manually-computed `int`-based `long` hash-code.
>> 
>> Because `Long#hashCode(long)` uses other hashing function than the one currently used here:
>> 
>> https://github.com/openjdk/jdk/blob/75d6688df9845ecb8f370b4cd2d5a36f13d3cdc0/src/java.base/share/classes/java/lang/Long.java#L1440-L1442
>> 
>> the value of `hashCode()` will produce different result, however this does not seem to be a breaking change as `UUID#hashCode()` is not specified.
>> 
>> ---
>> 
>> Note: the comment to the bug states:
>> 
>>> Moved to JDK for further discussions of the proposed enhancement.
>> 
>> But as there seemed to be no corresponding discussion in core-libs-dev and the change looks trivial, I considered that it is appropriate to open a PR which (if needed) may be used for discussion (especially, considering the fact that its comments get mirrored to the ML).
>
> Yes, the reverted change to BitSet.hashCode in https://github.com/openjdk/jdk/pull/4309 has the same property. It could be applied without any visible effect.

@plevart should I then file a follow-up ticket for `BitSet`? And should we change the JavaDoc providing there we have computation formula explicitly specified?

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PR: https://git.openjdk.java.net/jdk/pull/5811