Working with Google Collections
I have been working in an inherited codebase that uses the Google Collections library to extend the Collections in Java 5. I have to admit, they have done the set of classes that I'd have expected from Google - fits in with the existing objects, but adds those classes that can really be quite handy from, say, C++ and STL.
Multimap is one, missing in the JDK, but picked up by the Google Collections and implemented pretty nicely. They have the standard interface and then several implementations, each with it's particular plusses and minuses. I look at this very much in the same vein as the visualization library that I've been using for a while - very nice, but clearly done for something they had planned.
Not bad. I may spend a little more time looking into the library now that I've had to find it. Could be a nice addition like the visualization library.