RFR: 8268764: Use Long.hashCode() instead of int-cast where applicable [v2]

[Сергей Цыпанов]

On Wed, 30 Jun 2021 11:49:51 GMT, Сергей Цыпанов <github.com+10835776+stsypanov at openjdk.org> wrote:

>> In some JDK classes there's still the following hashCode() implementation:
>> 
>> long objNum;
>> 
>> public int hashCode() {
>>     return (int) objNum;
>> }
>> 
>> This outdated expression should be replaced with Long.hashCode(long) as it
>> 
>> - uses all bits of the original value, does not discard any information upfront. For example, depending on how you are generating the IDs, the upper bits could change more frequently (or the opposite).
>> 
>> - does not introduce any bias towards values with more ones (zeros), as it would be the case if the two halves were combined with an OR (AND) operation.
>> 
>> See https://stackoverflow.com/a/4045083
>> 
>> This is related to https://github.com/openjdk/jdk/pull/4309
>
> Сергей Цыпанов has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:
> 
>  - Merge branch 'master' into 8268764
>  - 8268764: Use Long.hashCode() instead of int-cast where applicable

Hi Kevin, thanks for review! I've updated copy-right year

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PR: https://git.openjdk.java.net/jdk/pull/4491