It was originally going to be a how to(What's incorrect? If I was wrong anywhere...I'd like to know.)
Constructive criticism: a good how to
will require much more than this. There isn't even any code demonstrations, a reasoning behind what generics actually accomplish, when they should be used, how to write classes which utilize the power of generics. I misread quite a bit of this post when I first read this (sorry, but it wasn't that hard to misread) and jumped to the gun that there were several mistakes (let be frank, you do have a tendency to provide incorrect advice). After going through it a bit more thoroughly I'd say its incorrect in calling it a how to and partially incorrect as the direct access of the contents of a Set - this could be debatable, but shows a slight mis-understanding on your part of what exactly a Set is.
My suggestion: if you want to write a how to I suggest you follow the outline some of the fantastic ones that can be found in the code snippets and tutorials thread, know your subject, write clear and concise, and if you don't know what something is (case in point Iterator) then look it up. How to's should NOT contain lines like "you may be able to do this somehow...though I'm not fully sure how exactly"