Whenever a new version of the language is released, a preponderance of the press attention goes to the simple langauge features that are both neat, and can be demonstrated quickly and effectively. So, with Java 7, much of the hype surrounded new language features such as the try-with-resources semantics, automatic resource management and fun things like numeric underscores and binary literals. But to be serious about Java 7, you need to move beyond the flashy new language features and dig into the new APIs that standardize concurrency and IO solutions.
In that vain, there are a couple of pretty good tutorials floating around that cover those two key topics. They're worth looking at if you're interested in getting up to speed on the latest Java 7 APIs.