RFR: 8357675: Amend headless message

[Alexey Ivanov]

On Mon, 26 May 2025 18:25:36 GMT, Phil Race <prr at openjdk.org> wrote:

> > > The existing message is fine. The comma is because it isn't done.
> > 
> > How is it not done?
> > > It introduces the exception text and the blank line adds some clarity. So nothing to change here.
> > 
> > 
> > Nothing goes after the comma, the exception message ends here, and the stack trace follows.
> 
> stack trace is what I mean by exception text.\
> The full text in the bug report reads better with a comma than a full stop. Is this text ever displayed without the stack trace following ? I can't remember.

The message can be extracted by [`Throwable.getMessage()`](https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/Throwable.html#getMessage()), then it can be displayed without the stack trace.

The stack trace is optional.

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PR Comment: https://git.openjdk.org/jdk/pull/25453#issuecomment-2910416396