Message1188

Anand Chitipothu sent this into jython dev and user. 
http://article.gmane.org/gmane.comp.lang.jython.user/4726

The exception occurs when jython code calls
SwingUtilities.invokeAndWait(or anything that puts code
on a thread and waits for its result) and the code run
on the event dispatch thread throws an exception.  When
a jython call descends into more jython code running on
another thread, the frame right after the threads
separate doesn't have f_back set to the previous frame.
 Since PyTableCode uses f_back to build tracebacks this
throws an NPE.