The first three things that struck me about this book were a very nice layout with tables, diagrams, screen shots etc. where required, a good-sized index and a lengthy chapter on Oracle SQL and PL/SQL basics. The book doesn't assume that you are familiar with Oracle's way of doing things so will appeal to a wider audience.
It covers the standard 'Hello World' application and how to pre-compile the SQLJ file into a .java file. It includes Inserts, Updates, Selects and Deletes from normal relational tables and Oracle Object Tables and nested tables, multi-threaded, session contexts and static/dynamic SQL with nicely detailed complete code that works.
A good detailed book on all the major functionality you require to use and run SQLJ in Java.