I like the book
Effective Java, which was written by a close friend of a professor of mine, and I've found to be a good resource for some of the nuances of Java that don't normally get covered in beginner tutorials (such as best practices). It also has sections for the C programmer that's moving to Java.
Also, the #1 resource of any Java programmer is the
API (1.4.2). It contains all the documentation for the core library classes.