Package will not be available at compile time in Java 9. Use java.awt.Desktop instead. See JEP 272 'Platform-Specific Desktop Features': http://openjdk.java.net/jeps/272
app.addAppEventListener(frame);
public MacOSAppEventDispatcher(final Application app, final EventService eventService) { this.eventService = eventService; app.setAboutHandler(this); app.setPreferencesHandler(this); app.setPrintFileHandler(this); app.setQuitHandler(this); app.addAppEventListener(this); app.setOpenFileHandler(this); }