In the code snippet under "Contravariant collections" section with class Generics the class Dog is missing.

Thanks I fixed that

Really nice article.
Wonderful way to explain Generics and Variance with runnable examples !

Thanks a lot

There are two "Declarion-site" in the text, typo maybe?

Hi, I don't quite know what you mean exactly, Can you point out the sentences please?

You mistyped "declaration" as "declarion" at three points in the post, just Ctrl+F it :) Didn't notice until I read this comment though.