Tinkering around with java generics

And now for something totally geeky. Of interest only to those programmers whose programming interests encompass both java generics and functional languages that tend to represent lists as singly linked lists most of the time. This is just kind of wandering about, with no coherent theme or conclusion to the post.
( (Haskell-style lists in java, with generic type safeness) )

Update: figured out a better way to do append in the ? extends E model.