Google App Engine Adds Support for Java 7
Google App Engine introduces experimental support for Java 7, Cloud Endpoints, and Cloud Messaging Service for Android.
One of the most interesting features introduced by Google in App Engine 1.7.5 is support for Java 7. While still an experimental feature, Google recommends using it for applications because it is fully backward compatible with previous Java versions and they intend to stop supporting Java 6 in an upcoming unspecified GAE version. Java 7 deployment is enabled through the compiler command line or Eclipse/Maven configuration. The JRE Class White List contains all the classes that can be used in a GAE application.
Google plug-in for Eclipse has been enhanced allowing developers to create back end applications that can use the Google Cloud Messaging Service for Android (GCM) which sends messages up to 4KB to Android devices. Message queuing and deliver is handled by the service without any charge.
Front end (F4) and back end (B4) instances now can have up to 1GB of memory instead of maximum 512 MB as it was before.
One last feature made generally available in 1.7.5 is the ability to be notified on bounced emails.
Ian Culling, Andy Powell & Lee Cunningham Dec 11, 2013