I find it really frustrating when the URLs in Sun-produced text books are broken.
This is inexcusable! Rather than break them, there should be a pointer to the new version of the topic and a pointer to the archived original topic.
As an recent convert to Java, I have been buying the textbooks from Amazon marketplace. One of them came without a companion CD and it has been quite difficult tracing the curren online versions of, for example, the Java Cryptography specification (Now renamed to JCE) and the Drag & Drop spec looks like it is still in revision state!
Not only that but the web site has links to ftp.java.sun.com which no longer appears to exist!
Please, Sun, try to keep some consistency with your links and terminology!