RFR: 8357996: Use "stdin.encoding" for reading System.in with InputStreamReader/Scanner [build/tools] [v2]

[Volkan Yazici]

On Mon, 2 Jun 2025 11:22:21 GMT, Volkan Yazici <vyazici at openjdk.org> wrote:

>> Passes the `Charset` read from the `stdin.encoding` system property while creating `InputStreamReader` or `Scanner` instances for `System.in`.
>> 
>> `stdin.encoding` is a recently added property for Java 25 in [JDK-8350703](https://bugs.openjdk.org/browse/JDK-8350703). Employing it throughout the entire code base is addressed by the parent ticket [JDK-8356893](https://bugs.openjdk.org/browse/JDK-8356893). JDK-8357996 this PR is addressing is a sub-task of JDK-8356893 and is concerned with only areas related to build and tools.
>
> Volkan Yazici has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Provide fallback for `stdin.encoding` in `ExternalEditor`

src/utils/src/build/tools/commentchecker/CommentChecker.java line 197:

> 195:             try {
> 196:                 BufferedReader br =
> 197:                     new BufferedReader(new InputStreamReader(System.in, System.getProperty("stdin.encoding")));

Not providing a `Charset` fallback – `CommentChecker` build tool should better fail if an invalid `stdin.encoding` is configured.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25541#discussion_r2120845904