Apart from text books, there are excellent java resources on the web. Since Java was devloped by Sun, their site is still important:

http://java.sun.com/

Their tutorial is available online. Some other sites with links are:

http://en.wikipedia.org/wiki/Java_programming_language

http://www.freewarejava.com/tutorials/index.shtml

http://www.apl.jhu.edu/~hall/java/FAQs-and-Tutorials.html

http://www.javacoffeebreak.com/

You can get good Java programming tips at:

http://www.javaworld.com/columns/jw-tips-index.shtml