I think the book does a good job of hitting this market. It is not suited to be a main textbook for a class, and it does not try to do that, But it does do a nice job of succinctly hitting the major points, providing nice examples,
As well as a reference for the major important topics.
So I see this as a nice book for developers who want to quickly (and cheaply) master networking Java, as well as a supplemental book for courses in continuing education courses or colleges.