..multi-posting?  
<http://www.physci.org/codes/javafaq.html#xpost>

My advice is "Don't".

I undertook a similar quest a few of years ago and chose the two
volume "Core Java" <http://horstmann.com/corejava.html>. I don't think
it was the wrong choice but I have since decided that "a thorough
reference book" for Java is not possible because of the huge and ever
expanding Java libraries. If you want bedside reading buy them but if
you want a reference while you work buy a second monitor to emulate a
book beside your existing monitor. I think all the information you are
ever likely to need is available in help files or free on the web but,
if not, you can supplement it at a much lower cost from Safari
<http://www.safaribooksonline.com/index.php>.

I would say Marty Hall's books.  He explains stuff about
communications nobody else touches.  
Core Web Programming, Second Edition
See http://mindprod.com/jgloss/who.html

Head First Java

I learned on this one, Complete Java 2 Certification Study Guide.
Whether you are going for a certification or not.  The less text more
code is awesome, and it covers the language real well.

http://tinyurl.com/2zjgeh
(links to amazon.com)

The Core Java I and II books are hands down the best Java books (and
references) I have ever come across.  They are very useful for real
work.

- Kurt