The file src/org/apache/pig/newplan/PColFilterExtractor.java is empty. It looks like its soul but not its earthly vessel left in 6b162e4b01b1a624fc59f93a160b37791df45026,
The empty file forces reassembly of the jar on every build even if nothing material had changed. Is there a reason for this file to exist as empty? If so, it should instead have a '/* (placeholder) */' line or something.
Trivial patch attached.