how do add a new filed and sort on this field

[Mr Shore]

I've just launched nutch in eclipse very hard
and now I want to add this sorting feature
but I don't know which file(s) should I modify to make it work?
I don't want to add a plugin because it's too much complicated for me now
what I want to do is just modify a few rows in certain files and that's all
Any advice is greatly apreciated!