What's the differences between Cocoon and servlet+XSL ?

[smallufo]

I tried Cocoon , followed the steps mentioned in "Java and XML". Now , I can use servlet+XSL , and the result is the same ( except XSP ) . Except for XSP (which I am not very appreciate , because I think it mix the logic with presentation . Well , maybe because I don't understand the essence of XSP ) , I don't know what is the difference between Cocoon and servlet+XSL  , can anybody explain it ?   Thank you.