RFR: 8353741: Eliminate table lookup in UUID.toString [v6]

[Shaojin Wen]

On Tue, 20 May 2025 19:51:14 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

>> Shaojin Wen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   hex8 comments
>
> src/java.base/share/classes/java/util/UUID.java line 528:
> 
>> 526:      * <pre>
>> 527:      * Input:  0x0123456789ABCDEF
>> 528:      * Output: 0x3031323334353637 ('0','1','2','3','4','5','6','7' in ASCII)
> 
> Only the low 32 bits are used, the example only needs to show the input ox 0x0123457.
> Or change the signature to accept an `int`.

Because the input of Long.expand is long, if the parameter is int, it will cause a redundant conversion process of long -> int -> long.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22928#discussion_r2098934998