The guys at Google took their time, but the much anticipated Google Collections 1.0 have finally been released. I expect this library to change the way we write our Java code (at least it did that to mine), so I put together an overview article to get you started.
At work I already use Google Collections, mostly for Multimaps, preconditions and immutable collections. It complements the JDKs collections framework nicely and I'm very happy with the APIs and documentation. In my opinion, the library belongs in every Java programmers' toolbox.
Java as a language may be losing heavily to competitors, but it's good to see that the Java platform and the whole ecosystem with its frameworks and libraries is still going strong.