For general information on Java, there is a FAQ maintained on the comp.lang.java newsgroup; it is available at http://www.city-net.com/~krom/java-faq.html.
There is an older FAQ-style document by Joey Oravec joey@sun.science.wayne.edu which primarily refers to the alpha release. You can find it at http://www.science.wayne.edu/~joey/java/linux.html. At some point these documents may merge.
Here are some Java-related pages: