Re: RFR: 8268764: Use Long.hashCode() instead of int-cast where applicable [v3]
On Thu, 1 Jul 2021 10:38:24 GMT, Сергей Цыпанов
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 This outdated expression should be replaced with Long.hashCode(long) as it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 incrementally with one additional
> commit since the last revision:
>
> 8268764: Update copy-right year
Right, done!
-
PR: https://git.openjdk.java.net/jdk/pull/4491
Re: RFR: 8268764: Use Long.hashCode() instead of int-cast where applicable [v3]
On Thu, 1 Jul 2021 10:38:24 GMT, Сергей Цыпанов
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 This outdated expression should be replaced with Long.hashCode(long) as it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 incrementally with one additional
> commit since the last revision:
>
> 8268764: Update copy-right year
Marked as reviewed by kevinw (Committer).
OK, one more (C) in
src/jdk.jdi/share/classes/com/sun/tools/jdi/ReferenceTypeImpl.java and done. 8-)
Needs a second Review before integrating, thanks.
-
PR: https://git.openjdk.java.net/jdk/pull/4491
Re: RFR: 8268764: Use Long.hashCode() instead of int-cast where applicable [v3]
> 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 incrementally with one additional
commit since the last revision:
8268764: Update copy-right year
-
Changes:
- all: https://git.openjdk.java.net/jdk/pull/4491/files
- new: https://git.openjdk.java.net/jdk/pull/4491/files/12a1d3ac..932c26ad
Webrevs:
- full: https://webrevs.openjdk.java.net/?repo=jdk=4491=02
- incr: https://webrevs.openjdk.java.net/?repo=jdk=4491=01-02
Stats: 6 lines in 6 files changed: 0 ins; 0 del; 6 mod
Patch: https://git.openjdk.java.net/jdk/pull/4491.diff
Fetch: git fetch https://git.openjdk.java.net/jdk pull/4491/head:pull/4491
PR: https://git.openjdk.java.net/jdk/pull/4491
