What does “Recursive type bound” in Generics mean?

Question

I am reading the chapter on Generics from Effective Java[Item 27].

There is this paragraph in the book:

It is permissible, though relative

Answer 1

There is an entry in the Java Generics FAQ written by Angelika Langer which explains the details of such declaration: http://www.angelikalanger.com/GenericsFAQ/FAQSections/TypeParameters.html#FAQ106