There is a wealth of material for Java on Sun's Java Web site http://java.sun.com including tutorials, papers, and APIs. To learn more about DrJava, see the Web site http://www.drjava.org/. Thinking in Java by Bruce Eckel is a good book for those who have some coding experience and like to understand a language deeply. Beginners might want to start with Headfirst Java by Kathy Sierra and Bert Bates. If you are someone who wants lots and lots of examples, see Deitel and Deitel's Java, How to Program.