FULL PRODUCT VERSION :
JRE version 1.6.0_19-b04

ADDITIONAL OS VERSION INFORMATION :
Windows Vista Home Basic

EXTRA RELEVANT SYSTEM CONFIGURATION :

A DESCRIPTION OF THE PROBLEM :
An applet (drag source) can't transfer data to another one (drop target) via Drag and Drop.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Implement an Applet that receives DnD content, display it in a browser and Drag and Drop any appropriate object on to it.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The applet receives Drag and Drop content.
ACTUAL -
Since update 1.6.0_19  drop security  exception is raised.


ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "AWT-EventQueue-8" java.security.AccessControlException: access denied
 (java.awt.AWTPermission accessClipboard)
        at java.security.AccessControlContext.checkPermission(Unknown Source)
        at java.security.AccessController.checkPermission(Unknown Source)
        at java.lang.SecurityManager.checkPermission(Unknown Source)
        at java.lang.SecurityManager.checkSystemClipboardAccess(Unknown Source)
        at sun.awt.dnd.SunDropTargetContextPeer.getTransferData(Unknown Source)
        at sun.awt.datatransfer.TransferableProxy.getTransferData(Unknown Source)
        at java.awt.dnd.DropTargetContext$TransferableProxy.getTransferData(Unknown Source)
        ...


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.*;
import java.awt.dnd.*;
import java.awt.datatransfer.*;

public class DndApplet extends javax.swing.JApplet {
    public void init() {
	DropTarget dt = new DropTarget(this, new DropTargetAdapter() {
	    public void drop(DropTargetDropEvent dtde) {
		Transferable transferable = dtde.getTransferable();
	    	DataFlavor[] flavors = transferable.getTransferDataFlavors();
		for(int i=0; i < flavors.length; i++) {
	    	    DataFlavor flavor = flavors[i];
    		    Class repClass = flavor.getRepresentationClass();
	    	    if (repClass.equals(String.class)) {
            		dtde.acceptDrop(dtde.getSourceActions());
	    		try {
		    	    Object object = transferable.getTransferData(flavor);
			    System.out.println("Accepted string "+object);
			    return;
			}
			catch (Exception ex) {
		    	    	ex.printStackTrace();
    	    		}
		    }
    	    	}
		dtde.rejectDrop();
	    }
	});
    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
No Workaround.
This doesn't work even if the drag source is another applet located at the same codebase.

Release Regression From : 6u18
The above release value was the last known release where this 
bug was not reproducible. Since then there has been a regression.