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

*** 105,118 ****
              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:
--- 105,114 ----
*** 135,144 ****
--- 131,145 ----
              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);