<i18n dev> RFR: 8311188: Simplify and modernize equals and hashCode in java.text [v4]

[Pavel Rappo]

On Wed, 5 Jul 2023 17:44:52 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

>> You are right, I have no stats. Performance-wise, it's already better than what was there before. Before, there was no short-circuit check. But I can go either way; I don't have a strong opinion.
>> 
>> Reusing superclass' equals is not often seen these days (and that code is old), so some amount of overlap is expected. Regardless of whether we rearrange that check or not, if the passed object is not `this`, we end up checking `this == obj` twice: once in super.equals, the other time in here.
>
> True, there's no simple way to avoid the double check in either the equal or not equal case.
> And I don't know enough about the Hotspot compiler to know whether it would spot the duplication and optimize it.
> In many `equals` methods, the test for self equality is frequently the first line.
> Is fine as is.

Re-arranged the checks in f1ce3a1. You are right, this way is more conventional. As a bonus, we can dispense with the comment.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14752#discussion_r1254322430