In the thursday keynote at Devoxx, Mark Reinhold (from Sun) presented the new features slated for the Java 7 release. (the expected release date of Java 7 is early 2010)
One of the most important new features will be the modularization of Java SE7. Modularization is needed because both Java and the JDK have become quite big. This for example gives issues when trying to run it on smaller (mobile) devices. Cutting the JDK into modules will avoid loading unnecessary classes, which on their turn result in shorter start-up times for applications. To print a simple string “Hello world”, Java needs over 300 classes in the current version!.
A list of the other new features can be found here!