While chasing down an issue on Mac with application events, we have noticed that there is some code under a private package that apparently it is supposed to be used by developers, which of course it is discouraged: com.sun.glass.ui.Application:EventHandler [1] is a public static inner class under a private package, that is added to the Application class for subclassing.
So far, only QuantumToolkit does subclass it [2] (just for Quit action and Theme changed events). However the EventHandler class has more methods for listening to MacOS/iOS application events. While most of those events happen before the app starts (and it wouldn't make sense to try to listen to them app-wise), in particular, the OpenFilesAction event is forwarded [3] when a second EventHandler is set. Other events like resign/become active actions can be listened to as well. A developer could provide a subclass of such EventHandler if it were public API, but so far, that has to be done accessing private API. At this point, and following on this other thread [4] that discussed a similar issue with EventHandlerManager, we should start considering the design of new public API that could provide developers with access to such events, with considerations to possible platform specifics. Regards, Jose [1] https://github.com/openjdk/jfx/blob/master/modules/javafx.graphics/src/main/java/com/sun/glass/ui/Application.java#L45 [2] https://github.com/openjdk/jfx/blob/master/modules/javafx.graphics/src/main/java/com/sun/javafx/tk/quantum/QuantumToolkit.java#L352 [3] https://github.com/openjdk/jfx/blob/master/modules/javafx.graphics/src/main/java/com/sun/glass/ui/Application.java#L346 [4] https://mail.openjdk.java.net/pipermail/openjfx-dev/2020-October/027909.html --