Java 7 has a number of features that will please developers. Madhusudhan Konda provides an overview of these, including strings in switch statements, multi-catch exception handling, try-with-resource statements, the new File System API, extensions of the JVM, support for dynamically-typed languages, and the fork and join framework for task parallelism.
Nice intro in the changes to the language but not that well balanced I would have liked some more details in the part about supporting dynamism. It doesn't do more than saying it exists. No code sample either. The part about switching on strings is so trivial it could have done without a code sample.
I choose this book to know about the changes and New feature in java 7. Air need to say that the author has done a wonderful job. He has put out some new features and upgrades in a short manner. It's a free book a plus and amazing double plus.
It is not really a book, there are articles longer than the this 10-pages book. But actually the contents of this so called book are as the title says, what is new in Java 7. Straight to the point. Read it, and you are on your way to start using JDK7.