Having a webpage with embedded video:
e.g. <video controls><source src="video\myVideo.mp4" type="video/mp4">Sorry no movie-file</video>

# If the video file does not exist, there is no feedback reporting this to the user (except if webview logger is turned on, then user sees an IOException in the console).
# The play button on the media player is NOT disabled.
# If then the play button is pressed, an IllegalThreadStateException is displayed in the console (see below)


java.lang.IllegalThreadStateException
at java.lang.Thread.start(Thread.java:704)
at com.sun.javafx.webkit.prism.WCMediaPlayerImpl.prepareToPlay(WCMediaPlayerImpl.java:208)
at com.sun.webkit.graphics.WCMediaPlayer.fwkPrepareToPlay(WCMediaPlayer.java:290)
at com.sun.webkit.WebPage.twkProcessMouseEvent(Native Method)
at com.sun.webkit.WebPage.dispatchMouseEvent(WebPage.java:742)
at javafx.scene.web.WebView.processMouseEvent(WebView.java:1004)
at javafx.scene.web.WebView.access$2500(WebView.java:76)
at javafx.scene.web.WebView$14.handle(WebView.java:1130)
at javafx.scene.web.WebView$14.handle(WebView.java:1128)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3712)
at javafx.scene.Scene$MouseHandler.access$1800(Scene.java:3440)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1663)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2455)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:326)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:251)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:360)
at com.sun.glass.ui.View.handleMouseEvent(View.java:526)
at com.sun.glass.ui.View.notifyMouse(View.java:898)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$300(WinApplication.java:39)
at com.sun.glass.ui.win.WinApplication$4$1.run(WinApplication.java:112)
at java.lang.Thread.run(Thread.java:744)