This is "only" a reference for the Spring platform - and a rather good reference. Johnson et. al. cover almost every important Spring topic in depth. The examples are useful and of real value, the same goes for the example application, which is discussed meticulously.
And although this book delivers what its title promises I felt like something was missing. The two books I mentioned above serve as architectural guidelines for developing J2EE applications - with or without Spring. This book however leaves the reader stranded with a wealth of Spring knowledge but without any sort of real tutorial.
So if you are rather firm in AOP and J2EE, add one star to my recommendation. The same holds if you own one of the other Johnson books. But if you are searching for a Spring tutorial you may have to look elsewhere...
And one last caveat: this book covers Spring < 2.0.