Google's PaaS Platform, AppEngine has been seeing consistent releases every month. The October release was different from the earlier one. In addition to the usual set of fixes and enhancements, the latest release 1.7.3 also sees support for new Java 7 Language features, while the Python 2.7 runtime now fully supports Django 1.4.
The AppEngine 1.7.3 release makes a strong statement by announcing its support for new Java 7 language features. Key language features supported include ability to use the String class in Switch statements, single catch blocks that can handle multiple exception, Auto closing of resources when enclosed within a try-with-resources statement and more. Refer to this O'Reilly eBook for new language features in Java 7 (Project Coin).
The Java 7 language support can only be tested out in the local development server and not in the runtime environment. The announcement does say that there are plans for the runtime environment to have support in a later release but no timeline has been provided for that. In case you want to try out these features in the runtime, you will need to sign up for the Trusted Tester program.