An area of java.sun.com for Java developers. There are forums to get support from other developers, downloads of early access software releases, JavaSoft bug tracking, tech tips, code samples, articles, and more.
See it at: http://developer.java.sun.com
The forums are sometimes a great resource for getting help when you need it. However, I have to say that the quality of the postings in the JDC is dismal these days. Some noble souls try to help these newbies out, and good for them, but it is usually to no avail. I have often found google to be a better source for solid information than the forums.
Not to discourage anyone from checking it out, though, as I have often gotten answers to tough questions there, and occasionally helped someone else out.
And it's always good for a laugh.