We try to implement a drag and drop function in jquery on our application using a javaFX WebView (see https://github.com/dahuapp/Dahu/issues/14 ) .
The drag and drop works well on Windows 7 and Mac systems but exception are risen on Linux (tested on Ubuntu 12.04 and Debian, x86_64).

Here is the stack trace of the problem :

Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
    at javafx.scene.web.WebView$18.handle(WebView.java:1173)
    at javafx.scene.web.WebView$18.handle(WebView.java:1165)
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:69)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:217)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:33)
    at javafx.event.Event.fireEvent(Event.java:171)
    at javafx.scene.Scene$DnDGesture.handleExitEnter(Scene.java:2878)
    at javafx.scene.Scene$DnDGesture.processTargetEnterOver(Scene.java:2775)
    at javafx.scene.Scene$DnDGesture.access$6100(Scene.java:2607)
    at javafx.scene.Scene$DropTargetListener.dragOver(Scene.java:2534)
    at com.sun.javafx.tk.quantum.GlassSceneDnDEventHandler$4.run(GlassSceneDnDEventHandler.java:126)
    at com.sun.javafx.tk.quantum.GlassSceneDnDEventHandler$4.run(GlassSceneDnDEventHandler.java:117)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.quantum.GlassSceneDnDEventHandler.handleDragOver(GlassSceneDnDEventHandler.java:117)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleDragOver(GlassViewEventHandler.java:422)
    at com.sun.glass.ui.View.handleDragOver(View.java:701)
    at com.sun.glass.ui.View.notifyDragOver(View.java:1010)
    at com.sun.glass.ui.gtk.GtkDnDClipboard.pushToSystemImpl(Native Method)
    at com.sun.glass.ui.gtk.GtkDnDClipboard.pushToSystem(GtkDnDClipboard.java:24)
    at com.sun.glass.ui.SystemClipboard.flush(SystemClipboard.java:28)
    at com.sun.glass.ui.ClipboardAssistance.flush(ClipboardAssistance.java:34)
    at com.sun.javafx.tk.quantum.QuantumClipboard.flush(QuantumClipboard.java:197)
    at com.sun.javafx.tk.quantum.QuantumToolkit.startDrag(QuantumToolkit.java:1195)
    at javafx.scene.Scene$DnDGesture.dragDetectedProcessed(Scene.java:2652)
    at javafx.scene.Scene$DnDGesture.process(Scene.java:2713)
    at javafx.scene.Scene$DnDGesture.access$8700(Scene.java:2607)
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3344)
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3168)
    at javafx.scene.Scene$MouseHandler.access$1900(Scene.java:3123)
    at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1563)
    at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2265)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:250)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:173)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:292)
    at com.sun.glass.ui.View.handleMouseEvent(View.java:528)
    at com.sun.glass.ui.View.notifyMouse(View.java:922)
    at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
    at com.sun.glass.ui.gtk.GtkApplication$3$1.run(GtkApplication.java:82)
    at java.lang.Thread.run(Thread.java:722)

We use the java version 1.7.0_21