RFR: 8344706: Implement JEP 512: Compact Source Files and Instance Main Methods [v5]

[Tatsunori Uchino]

On Sun, 27 Apr 2025 14:23:50 GMT, Tatsunori Uchino <duke at openjdk.org> wrote:

>> I misunderstood that I have tested `stdin.encoding`.
>> I cannot confirm that `stdin.encoding` is changed in Windows to proper ones because it has not been included in the latest EA build (20) and I cannot build master for Windows. However, it is changed to `US-ASCII` in Ubuntu when I change `LANG`. I will believe its author until the latest EA build is updated.
>
> Anyway you need to merge master first to test `stdin.encoding`.

`stdin.encoding` seems to work as intended in Windows for Japanese. No need to change. (I wish the constructors of `InputStreamReader` and `Scanner` used `stdin.encoding` instead of UTF-8 for `System.in` by defaultI) Sorry to have bothered you.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24438#discussion_r2070108439