I learned a lot at JavaOne. It was a great experience. Here are a few things I learned about (with links to my notes):
Java 7: you can benefit from it even without using new features.
Grails 2: a huge improvement over Grails 1, and Grails 2.2 will use Groovy 2 (with the new static type checking features, among others).
PlayFramework 2: A framework using the Akka concurrency model, which can work with either Scala or Java.
Concurrency without pain in pure Java: Awesome talk about using features from Akka and Clojure to simplify concurrency in Java.
Also, James Gosling was there at the community keynote, which was awesome. I’m more convinced now that Oracle will be a good steward of Java going forward. The adopt-a-jsr project seems like a good step.
You can download tons of free content from javaone (by going to Tools - Content Catalog), including videos!