src/macosx/classes/sun/lwawt/macosx/CDragSourceContextPeer.java

@@ -105,14 +105,10 @@
             dragOrigin.translate(loc.x, loc.y);
             rootComponent = rootComponent.getParent();
             loc = rootComponent.getLocation();
         }
 
-        //It sure will be LWComponentPeer instance as rootComponent is a Window
-        PlatformWindow platformWindow = ((LWComponentPeer)rootComponent.getPeer()).getPlatformWindow();
-        long nativeViewPtr = CPlatformWindow.getNativeViewPtr(platformWindow);
-
         // If there isn't any drag image make one of default appearance:
         if (fDragImage == null)
             this.setDefaultDragImage(component);
 
         // Get drag image (if any) as BufferedImage and convert that to CImage:

@@ -135,10 +131,15 @@
             fDragCImage = null;
             dragImageOffset = new Point(0, 0);
         }
 
         try {
+            //It sure will be LWComponentPeer instance as rootComponent is a Window
+            PlatformWindow platformWindow = ((LWComponentPeer)rootComponent.getPeer()).getPlatformWindow();
+            long nativeViewPtr = CPlatformWindow.getNativeViewPtr(platformWindow);
+            if (nativeViewPtr == 0L) throw new InvalidDnDOperationException("");
+
             // Create native dragging source:
             final long nativeDragSource = createNativeDragSource(component, nativeViewPtr, transferable, triggerEvent,
                 (int) (dragOrigin.getX()), (int) (dragOrigin.getY()), extModifiers,
                 clickCount, timestamp, fDragCImage, dragImageOffset.x, dragImageOffset.y,
                 getDragSourceContext().getSourceActions(), formats, formatMap);