I'm a fan of the effective series of books (Effective Java, Effective C# etc.)and was therefore looking forward to this book hoping to pick u a few gems I'd yet to discover. To be blunt I was disappointed. The book is well written and concise, however having done considerable Java development I found this book more of a nostalgic reminder of the advances Java had given us when it first appeared in the late nineteen nineties.
I think this book might be of use to somebody newer to the Java language who has already gotten to grips with the basics of the language as it does cover many of the topics I found I had already learnt with a combination of playing with the language and reading during my early days programming Java. However for those more experienced I think Effective Java would be a better investment of your time as I feel any reasonably experienced Java developer will find very little new information in this book.