Article : Cut And Paste Detector.

http://www.onjava.com/pub/a/onjava/2003/03/12/pmd_cpd.html

The list of C&P sections of the java source base is great...Dion Almaer over at O'Reilly mentioned the idea of a concept detector, as in detecting when someone writes a utility function that's been implemented by someone else already...I could go for that, but I'd like it tied in to existing opensource code bases like Jakarta Commons.