Start Notepad.jar using jdk 7.0 b16 or later.
Try to drop any icon from desctop to Notepad text area.

Observe following exception thrown to the console:

java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer
at javax.swing.TransferHandler$DropHandler.initPropertiesIfNecessary(TransferHandler.java:1346)
at javax.swing.TransferHandler$DropHandler.dragEnter(TransferHandler.java:1433)
at java.awt.dnd.DropTarget.dragEnter(DropTarget.java:354)
at javax.swing.TransferHandler$SwingDropTarget.dragEnter(TransferHandler.java:1175)
at sun.awt.dnd.SunDropTargetContextPeer.processEnterMessage(SunDropTargetContextPeer.java:313)
at sun.awt.dnd.SunDropTargetContextPeer$EventDispatcher.dispatchEnterEvent(SunDropTargetContextPeer.java:777)
at sun.awt.dnd.SunDropTargetContextPeer$EventDispatcher.dispatchEvent(SunDropTargetContextPeer.java:745)
at sun.awt.dnd.SunDropTargetEvent.dispatch(SunDropTargetEvent.java:48)
at java.awt.Component.dispatchEventImpl(Component.java:4277)
at java.awt.Container.dispatchEventImpl(Container.java:2132)
at java.awt.Component.dispatchEvent(Component.java:4250)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4267)
at java.awt.LightweightDispatcher.trackMouseEnterExit(Container.java:4056)
at java.awt.LightweightDispatcher.processDropTargetEvent(Container.java:3994)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3856)
at java.awt.Container.dispatchEventImpl(Container.java:2118)
at java.awt.Window.dispatchEventImpl(Window.java:2554)
at java.awt.Component.dispatchEvent(Component.java:4250)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:612)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:276)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:191)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:186)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:178)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:139)
java.lang.NullPointerException
at sun.awt.dnd.SunDropTargetContextPeer$EventDispatcher.<init>(SunDropTargetContextPeer.java:736)
at sun.awt.dnd.SunDropTargetContextPeer.postDropTargetEvent(SunDropTargetContextPeer.java:545)
at sun.awt.dnd.SunDropTargetContextPeer.handleExitMessage(SunDropTargetContextPeer.java:341)
at sun.awt.windows.WToolkit.eventLoop(Native Method)
at sun.awt.windows.WToolkit.run(WToolkit.java:285)
at java.lang.Thread.run(Thread.java:644)
Exception in thread "AWT-Windows"

No exception is thrown using b15, b13 or b01.