Name: mm8553 Date: 05/17/99


1.DragGestureEvent.startDrag() with parameter Transferable=null
  crashes VM.
  If I have a Transferable object which is a null reference
  then the VM of this code snippet crashes!!! This occurs
  only if I drag and drop between different VMs, i.e. in the
  same VM it throws a NullPointerException.

2. Code:

 class DGListener implements DragGestureListener {

private int acceptableActions = DnDConstants.ACTION_MOVE;

public void dragGestureRecognized(DragGestureEvent e) {

System.out.println(e.getDragAction());
if((e.getDragAction() & acceptableActions) == 0) {
return;
}
      
Transferable transferable = new StringTransferable( null );
try {
e.startDrag(DragSource.DefaultCopyNoDrop,transferable,...);
}
catch( InvalidDnDOperationException idoe ) {
System.err.println( idoe );
}
}
}

3. When I drag and drop between the same VM:

java.lang.NullPointerException
        at edit.DTListener.drop(DTListener.java:147)
        at java.awt.dnd.DropTarget.drop(DropTarget.java:343)
        at sun.awt.windows.WDropTargetContextPeer.processDropMessage(WDropTarget
ContextPeer.java:941)
        at sun.awt.windows.WDropTargetContextPeer.run(WDropTargetContextPeer.jav
a:472)
        at javax.swing.SystemEventQueueUtilities.processRunnableEvent(SystemEven
tQueueUtilities.java:354)
        at javax.swing.SystemEventQueueUtilities.access$0(SystemEventQueueUtilit
ies.java:350)
        at javax.swing.SystemEventQueueUtilities$RunnableTarget.processEvent(Sys
temEventQueueUtilities.java:391)
        at java.awt.Component.dispatchEventImpl(Component.java:2376)
        at java.awt.Component.dispatchEvent(Component.java:2289)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:258)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:68)

  When I drag and drop between different VMs this is the error
  message of the DropTarget VM (not the DragSource VM which
  crashes!):

Couldn't get transfer data: class java.io.IOException:no native data was transfe
rred caught while getting Data
java.io.IOException: class java.io.IOException:no native data was transferred ca
ught while getting Data
        at java.awt.dnd.DropTargetContext$TransferableProxy.getTransferData(Drop
TargetContext.java:270)
        at edit.DropLabel$DTListener.drop(DropLabel.java:200)
        at java.awt.dnd.DropTarget.drop(DropTarget.java:343)
        at sun.awt.windows.WDropTargetContextPeer.processDropMessage(WDropTarget
ContextPeer.java:941)
        at sun.awt.windows.WDropTargetContextPeer.run(WDropTargetContextPeer.jav
a:472)
        at javax.swing.SystemEventQueueUtilities.processRunnableEvent(SystemEven
tQueueUtilities.java:354)
        at javax.swing.SystemEventQueueUtilities.access$0(SystemEventQueueUtilit
ies.java:350)
        at javax.swing.SystemEventQueueUtilities$RunnableTarget.processEvent(Sys
temEventQueueUtilities.java:391)
        at java.awt.Component.dispatchEventImpl(Component.java:2376)
        at java.awt.Component.dispatchEvent(Component.java:2289)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:258)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:68)

4. Dr. Watson from WinNT appears with a Segmentation Fault (0xc0000005); address (0x080370c0)
5. java version "1.2.1"
   HotSpot VM (1.0fcs, mixed mode, build E)
6. I have a PentiumII-400 with WinNT Service Pack 4 and 128MB
(Review ID: 58066)
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