Fatal error when resource cannot be resolved

[Greg Brown]

> recently I have localized my FX code. I noticed that the FXMLLoader would throw an exception if it cannot resolve a resource key. 
...
> This seems a bit drastic.

This was done to parallel the behavior of ResourceBundle, which throws a MissingResourceException when a resource is not found.

> Maybe it is better to show the unresolved key instead in the GUI? With some logging in place I would probably just log this as a warning.

This is a pretty easy exception to resolve. Why not just add the missing key to your resource bundle? 

Greg