The following piece of FXML does not load properly, because the file name contains spaces.
However, instead of failing to load, the FXMLLoader logs a message (see stack trace logged below),
and then calls LoadListener.endElement(null);

I think a better behaviour would be to propagate the exception - which would allow for a better reporting of what is going wrong.

    <MediaView id="01 Rolling In The Deep.m4a♫" layoutX="300.0" layoutY="200.0">
      <!-- SceneBuilder: Selection.locked="true" -->
      <mediaPlayer>
        <MediaPlayer cycleCount="-1">
          <media>
            <Media source="@../Music/iTunes/iTunes%20Music/Adele/21/01 Rolling In The Deep.m4a" />
          </media>
        </MediaPlayer>
      </mediaPlayer>
    </MediaView>


Jun 22, 2012 10:15:17 AM javafx.fxml.JavaFXBuilder$ObjectBuilder build
WARNING: Failed to build instance of class javafx.scene.media.Media using class javafx.scene.media.MediaBuilder
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at javafx.fxml.JavaFXBuilder$ObjectBuilder.build(JavaFXBuilderFactory.java:212)
at javafx.fxml.FXMLLoader$ValueElement.processEndElement(FXMLLoader.java:584)
at javafx.fxml.FXMLLoader.processEndElement(FXMLLoader.java:2421)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2129)
at com.oracle.javafx.authoring.persist.FXMLDocument.load(FXMLDocument.java:151)
at com.oracle.javafx.authoring.persist.LoadFxml$2.call(LoadFxml.java:66)
at com.oracle.javafx.authoring.persist.LoadFxml.loadElement(LoadFxml.java:140)
at com.oracle.javafx.authoring.persist.LoadFxml.loadScreenData(LoadFxml.java:182)
at com.oracle.javafx.authoring.Project.forFxml(Project.java:802)
at com.oracle.javafx.authoring.Project.forFxml(Project.java:778)
at com.oracle.javafx.authoring.DesignerTool.loadFXMLLayout(DesignerTool.java:142)
at com.oracle.javafx.authoring.DesignerTool.loadFXMLLayout(DesignerTool.java:131)
at com.oracle.javafx.authoring.ApplicationMenu$84.handle(ApplicationMenu.java:2617)
at com.oracle.javafx.authoring.ApplicationMenu$84.handle(ApplicationMenu.java:2614)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:69)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:217)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:28)
at javafx.event.Event.fireEvent(Event.java:171)
at javafx.scene.control.MenuItem.fire(MenuItem.java:455)
at com.sun.javafx.scene.control.GlobalMenuAdapter$6.handle(GlobalMenuAdapter.java:159)
at com.sun.javafx.scene.control.GlobalMenuAdapter$6.handle(GlobalMenuAdapter.java:157)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:69)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:217)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:33)
at javafx.event.Event.fireEvent(Event.java:171)
at javafx.scene.control.MenuItem.fire(MenuItem.java:455)
at com.sun.javafx.tk.quantum.GlassSystemMenu$6.action(GlassSystemMenu.java:219)
Caused by: java.lang.IllegalArgumentException: java.net.URISyntaxException: Illegal character in path at index 63: file:/Users/danielfuchs/Music/iTunes/iTunes%20Music/Adele/21/01 Rolling In The Deep.m4a
at javafx.scene.media.Media.<init>(Media.java:359)
at javafx.scene.media.MediaBuilder.build(MediaBuilder.java:65)
... 39 more
Caused by: java.net.URISyntaxException: Illegal character in path at index 63: file:/Users/danielfuchs/Music/iTunes/iTunes%20Music/Adele/21/01 Rolling In The Deep.m4a
at java.net.URI$Parser.fail(URI.java:2810)
at java.net.URI$Parser.checkChars(URI.java:2983)
at java.net.URI$Parser.parseHierarchical(URI.java:3067)
at java.net.URI$Parser.parse(URI.java:3015)
at java.net.URI.<init>(URI.java:577)
at javafx.scene.media.Media.<init>(Media.java:357)
... 40 more