I work with someone who swears by Thinking in Java. He hasn't been working with java for all that long, but his code is solid so I'd vouch for that book.
in reply to (OT) Recommendations for Java books
If you are looking to get up to date with the new bits added with java 1.5 then I recommend Java 5.0 Tiger: A Developer's Notebook. Java 1.6 is in beta currently so I'm sure there will be something comparable coming out soon - it looks like a nice release.
For J2EE work you might take a look at Enterprise JavaBeans 3.0, 5th Edition. Working with EJB used to make grown men cry, but with version 3.0 they are actually quite reasonable to work with. The book is very chatty and takes awhile to go through, but there is also a lot of content.
I picked up Java Reflection in Action recently and have found it very useful. In the past I considered reflection in java tedious, inefficient, and indicative of a design problem in my application. The performance issues have been addressed for the most part, and reflection has matured - particularly relating to annotations (a java 1.5 feature).
For threading I have heard good things about Java Concurrency in Practice, but haven't had a chance to read it yet.