RFR: 8270490: Charset.forName() taking fallback default value [v2]

[Naoto Sato]

On Thu, 21 Oct 2021 15:00:03 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

>> src/java.base/share/classes/java/io/Console.java line 594:
>> 
>>> 592:                 cs = Charset.forName(StaticProperty.nativeEncoding(), Charset.defaultCharset());
>>> 593:             } catch (Exception ignored) {
>>> 594:                 cs = Charset.defaultCharset();
>> 
>> What kind of actual improvements do we get here since the catch block is still in place?
>
> In the case of Console, both charset names come from system properties and could refer to invalid or unavailable charsets.  (null is handled separately).  The code silently ignores the invalid values.  The new method , as is, is not a fully satisfying replacement.  Catching Exception is too broad a catch but may be warranted in this case so that some Console charset is selected.
> 
> The new method would be useful in more cases if the default was returned for any of
> IllegalCharsetNameException, IllegalArgumentException, and UnsupportedCharsetException.

Since we do support all the encodings for platforms we support out-of-the-box, it could still be possible that the user can specify his/her console encoding to the one we do not support. In that case, we can safely use the default `UTF-8` without throwing/catching `UnsupportedCharsetException`.

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PR: https://git.openjdk.java.net/jdk/pull/6045