RFR: 8350703: Add standard system property stdin.encoding

[Naoto Sato]

On Thu, 17 Apr 2025 18:59:33 GMT, Stuart Marks <smarks at openjdk.org> wrote:

> * Windows and Unix: set sprops.stdin_encoding if connected to a console
> * Add specs for stdin.encoding
> * Adjust specs to change "undefined" to "unspecified"
> * Rewrite System.in spec to refer to new property and to clarify usage with classes that perform encoding
> * Update property test

Looks good. Is a corresponding CSR being drafted?

src/java.base/share/classes/jdk/internal/util/SystemProps.java line 92:

> 90: 
> 91:         // Encoding properties for stdin, stdout, and stderr. For stdout and stderr,
> 92:         // check "sun.*.encoding" properties before falling back to the

Could explain about sun* a bit more (just for compatibility) and stdin.encoding is free from it.

src/java.base/windows/native/libjava/java_props_md.c line 637:

> 635: 
> 636:         {
> 637:             HANDLE hStdIn;

Instead of creating a new variable, `hStdOutErr` could be reused with a proper name.

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PR Review: https://git.openjdk.org/jdk/pull/24738#pullrequestreview-2785735700
PR Review Comment: https://git.openjdk.org/jdk/pull/24738#discussion_r2055115841
PR Review Comment: https://git.openjdk.org/jdk/pull/24738#discussion_r2055116403