I find this a good "cook book" -the sort you need in a rush, to remind you the details. Although some items were rather too-commonly used to include in a reference (eg: "Q:You need to sleep for a while; A: use Thread.sleep()"), in general the tips were very useful.
I would recommend this for the novices and the experienced alike, to help free your mind with the details of Java coding intricacies, and let you worry about more important design /testing aspects. Personally I found this very useful in graphics and internationalization, the things that I do not use everyday work.