RFR: 8356245: stdin.encoding and stdout.encoding in jshell don't respect console code pages [v4]

[Christian Stein]

On Mon, 26 May 2025 15:29:09 GMT, Jan Lahoda <jlahoda at openjdk.org> wrote:

>> JShell, by default, uses two processes: the main one which compiles snippets, and a remote, that runs them.
>> 
>> The remote process is not connected to console, and hence its in/out/err encoding will be derived from the platform encoding, while the main process will use encoding derived from the console settings.
>> 
>> This PR proposes to pass the stdin/out/err encoding from the main process to the remote process. It also has to change the char->byte conversion for System.in to use the `stdin.encoding`, so that the remote process understands it.
>> 
>> The `InputUITest` requires explicitly setting encoding, as the tests sometimes run with the ASCII encoding, but use Unicode characters, and fail, as the ASCII encoding is not really followed by JShell now.
>
> Jan Lahoda has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Adding comment as suggested.

Marked as reviewed by cstein (Committer).

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PR Review: https://git.openjdk.org/jdk/pull/25328#pullrequestreview-2868780794