RFR: 8210336: DateTimeFormatter predefined formatters should support short time zone offsets [v4]

[Roger Riggs]

On Tue, 27 Jan 2026 23:56:36 GMT, Naoto Sato <naoto at openjdk.org> wrote:

>> This PR is a follow-on fix to [JDK-8032051](https://bugs.openjdk.org/browse/JDK-8032051), where it allowed short offsets only for ZonedDateTime parsing. This fix allows all predefined ISO formatters to accept short offsets. A corresponding CSR has been drafted.
>
> Naoto Sato has updated the pull request incrementally with one additional commit since the last revision:
> 
>   +00/-00 offsets tests

Looks good.

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Marked as reviewed by rriggs (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/29393#pullrequestreview-3716922549