At JavaOne 2012, Stuart Marks, Mike Duigou, and Joe Darcy gave a presentation about JDK 7 In Action. Learn more about using JDK 7 features with the help of Java Tutorials and JDK 7 Developer Guides. Links to relevant information are provided below.
If you are considering moving to JDK 7 from a previous release, the JDK 7 Release Notes and JDK 7 Adoption Guide are great resources.

Project Coin Features

Improved Literals

* Literals section in Primitive Datatypes topic.
* Binary Literals
* Underscores in Numeric Literals

Strings In Switch

* Strings In Switch

Diamond

* Type Inference for Generic Instance Creation
* Type Inference and Instantiation of Generic Classes

Multi-catch and Precise Throw

* Catching Multiple Exception Types and Rethrowing Exceptions with Improved Type Checking
* Catch Blocks

Try-with-resources

* The try-with-resources Statement

NIO.2 File System API

* File I/O for information on path, files, change notification, and more
* Zip File System Provider
* Zip File System Provider
* Developing a Custom File System Provider

Fork Join Framework

* Fork/Join


- Sowmya