During the christmas holiday I read a book about java parallel programming from Rainer Oechsle.
The book is a good introduction to the topic written which covers the main aspects. It is not a complete reference of all techniques of java but it gives you many ideas what you can do with it and where you have to research for further information. It also explain with many good examples why one way to solve a problem is good or bad and what you should keep in mind to get a good and stable application.
It covers the basic synchronize mechanism of java, advanced techniques new in Version 5, Graphical User Interfaces, distributed application with sockets, RMI and Servlets and JSP.
For all who want to do parallel programming in java this book is a good start in my opinion.