Jabref: Show proper error message for uncaught exceptions

[tobiasdiez]

JabRef latest version on Win 10

Steps to reproduce:

1. Add somewhere a throw new NPE() (for example, when showing the AboutDialog)
2. Perform the action which invokes this code
3. Nothing happens (e.g. no AboutDialog appears) but also no error message is displayed. (Although an error is logged in the error console.)

With https://github.com/JabRef/jabref/pull/2287 the uncaught error is logged properly, but still no error message is displayed to the user. However, the code in FallbackExceptionHandler can easily be adapted to show a message to the user, see e.g. http://www.javaspecialists.eu/archive/Issue196.html.
As there is an ExceptionDialog for JavaFX, I mark this issue as after-javafx.

[Le-wi]

Hi, I'd like to take this one :)

[tobiasdiez]

Happy new year! Feel free to work on this issue and also have a look at our contribution guide. Moreover, feel free to drop by in our developer chat if you have questions!

[Le-wi]

Happy new year as well :+1:

[Siedlerchr]

Thanks to @Le-wi this issue should be fixed in the latest master now!

[Le-wi]

This is so exciting, thanks for tagging beginner issues!

[tobiasdiez]

@Le-wi we have to thank you for your help! Looking forward to review the next PR from you ;-)