Making Meetup: New I/O sometimes better than Old I/O

makingmeetup:

We decided to try repackaging an internal service, which was running a servlet container, in a custom built NIO server. Its baseline request load fluctuates with user traffic on the site, but bursts of activity are produced by daemon processes, as shown in this graph of requests per second:

Another chart, and some explanation of what it represents, is found in the original post.

Can you guess what toolkit for servicing HTTP requests we used?