Programming Google App Engine with Java

Programming Google App Engine with Java teaches intermediate and advanced web developers how to build infinitely scalable applications with App Engine. Like Amazon's EC2, App Engine lets companies „rent“ cloud computing resources. This book describes ways to perform common development tasks using App Engine APIs and services, using App Engine's Java runtime environment. The Java runtime includes a complete Java 7 JVM capable of running bytecode produced by the Java compiler, as well as that produced by compilers for other languages that target the JVM. App Engine is a J2EE standard servlet container, and includes the standard libraries and features for Java web development. You can even deploy your apps as WAR files.
If you're a Python programmer, look for Dan Sanderson's companion volume Programming Google App Engine with Python.