While Java does not yet have the tool support of some other languages, the fact that you can do a single development and have it run on a variety of platforms outweighs this deficiency for many developers. Even if you have only clients of one type, Java may be a good choice. I'm currently slogging my way through more than a dozen books on Java. I will give a slew of mini-reviews in a month or two. I've yet to find one that shows no growing pains.
Every book leaves off details and has minor errors that are likely to confuse the new learner.
Some of the books are targeted at game writers, an application area that is attracting much attention because of the desire to run multi-player games over the Internet. They just lack descriptions of much of the networking and other new features. Fortunately, they are not important. The lay-flat binding is a nice touch. It is shorter on hints, tips and problem solving than most of the books on Warp 3.