Message2006

I'm using jython embedded in a web app.  When running in tomcat through eclipse (using the sysdeo tomcat plugin) I find that when I shutdown tomcat the PyFileCloser thread throws a NullPointerException.  This is caused by the closers static member of PyFile is null when the run method is called.  I'm not sure how this happens since closers is private, and statically intialized, and there doesn't seem to be any code that sets it to null.  None the less, it is happening, and the attached patch prevents this Exception.