<AWT Dev> [8] Review Request: JDK-8024163 [macosx] NullPointerException at javax.swing.TransferHandler$DropHandler.handleDrag since jdk8b93, 7u40b28

[Petr Pchelko]

Hello, AWT Team.

Please review the fix for the following issue:
https://bugs.openjdk.java.net/browse/JDK-8024163
The fix is available here:
http://cr.openjdk.java.net/~pchelko/8024163/webrev.00/

The problem is with the DropTarget Enter/Exit events. For real heavyweights they are generated by native code. For lightweights - in shared code. But for AWT components they should be generated in CDropTargetContextPeer.
Before the fix these events could be generated incorrectly: sometimes duplicated events were sent (this broke autoscrolling) and sometimes events were not sent at all - this caused NPEs in the shared code.
The insideTarget boolean was replaced by a reference to DropTarget to handle nested components correctly.

Tested on Mac OS X (no shared code affected). 
No new regression test failures.

With best regards. Petr.