RFR: 8356420: Provide examples on wrapping System.in [v4]

[Stuart Marks]

On Mon, 12 May 2025 21:59:29 GMT, Naoto Sato <naoto at openjdk.org> wrote:

>> With the introduction of `stdin.encoding` ([JDK-8350703](https://bugs.openjdk.org/browse/JDK-8350703)), some guidance for users to decode `System.in` would be desirable. Adding examples in the field description would help.
>
> Naoto Sato has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Reflects more comments

src/java.base/share/classes/java/util/Scanner.java line 89:

> 87:  *          String aLine = sc.nextLine();
> 88:  *      }
> 89:  * }

Now that I'm looking at the other examples, I have what I think is better example for using Scanner on System.in. Take this example and move it after the example below, which reads long values from the file `myNumbers`. The new example could do the same thing with the hasNextLong/nextLong loop. But instead it would read from System.in using the encoding specified by `stdin.encoding`. The example could explain that reading from files uses the default encoding (`file.encoding`) whereas reading from System.in should use `stdin.encoding` because on some systems this differs from the default encoding.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25155#discussion_r2085745213