[lworld] RFR: 8287241: Add IdentityException to report that a value object is not valid [v3]

[Mandy Chung]

On Thu, 9 Jun 2022 15:53:02 GMT, Rémi Forax <forax at openjdk.org> wrote:

>> It not clear where to draw the line on convenience methods (message can be null), but ok, added.
>
> It's a convenient method but it's not equivalent to calling IdentityException(null, cause), Throwable(cause) is equivalent to Throwable(cause.getMessage(), cause) which is important if later a logger is configured to only log the error message.

Exceptions in the JDK do not always have all four standard constructors as in `Throwable`.  There was a discussion to audit the constructor choices for JDK exceptions.  Some new exceptions do add all 4 constructors (`IllegalCallerException` and `WrongThreadException`).   Since this one has a constructor taking the `cause` for exception chaining, it's reasonable to add the variant setting the default message to `cause.getMessage()`.

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PR: https://git.openjdk.org/valhalla/pull/696