"Leverage the open source Restlet Framework and its unique Java API available in six consistent editions: Java SE, Java EE, OSGi, GAE, Android and GWT!"

"Slim3 is a full-stack MVC framework optimized for Google App Engine/Java, and you can use Slim3 as just a datastore framework, too." Claims to support global transactions between multiple entity groups.

the book...

the book

ze book

Google Application Engine is a darken profession technology that lets you separate scheme applications that are cushy to physique and reassert as substantially as existence scaled and load-balanced automatically. To physique engrossing and mutual scheme applications developers are motion to Java. However, antiquity and deploying ascendible scheme applications using Google Web Toolkit and Google App Engine for Java crapper be hard modify to developers. ...

arghh!

Twig is an object persistence interface built on Google App Engine's low-level datastore which overcomes many of JDO-GAEs limitations including full support for inheritance, polymorphism and generic types. You can easily configure, modify or extend Twigs behaviour by implementing your own strategies or overriding extension points in pure Java code.

I'm pleased to announce the release of bulkupdate, an unoriginally-named library for the App Engine Python runtime that facilitates doing bulk operations on datastore data. With bulkupdate, simple operations like bulk re-puts and bulk deletes are trivial, while more complex operations like schema transitions or even emailing all your users become much simpler.

ROME is a set of Atom/RSS Java utilities that make it easy to work in Java with most syndication formats:

ROME is an set of open source Java tools for parsing, generating and publishing RSS and Atom feeds. The core ROME library depends only on the JDOM XML parser and supports parsing, generating and converting all of the popular RSS and Atom formats including RSS 0.90, RSS 0.91 Netscape, RSS 0.91 Userland, RSS 0.92, RSS 0.93, RSS 0.94, RSS 1.0, RSS 2.0, Atom 0.3, and Atom 1.0. You can parse to an RSS object model, an Atom object model or an abstract SyndFeed model that can model either family of formats.

GAELucene is a lucene component that can help you to run search applications on Google AppEngine.

JDO and JPA code samples

The Web Sockets API enables web browsers to maintain a bi-directional communication channel to a server, which in turn makes implementing real-time web sites about 1000% easier than it is today.

Currently, the only reasonable technical facility available to browsers to communicate to web servers is XMLHttpRequest. Sites that update in real-time like FriendFeed use a number of horrible hacks on top of XMLHttpRequest like long-polling to get data in real-time. (If you are interested, Tornado ships with a chat demo application that uses this long-polling technique - here is the JavaScript in all its hacky glory).

Web Sockets support a much simpler interface that enables both the client and the server send messages to each other asynchronously

server push?

not available for java yet

inc. Task Queue

While initially promising, App Engine's Java-based persistence currently has some serious drawbacks, which I explain and demonstrate. You'll learn how App Engine for Java persistence works, what the challenges are, and also what persistence options you have when working with Google's cloud platform for Java developers.
As you read the article and work through the examples, you'll want to keep in mind the fact that the App Engine for Java is currently a preview release. While the Java-based persistence may not be all that you could hope for, or need, at present, that could and should change in the future. What I learned in the writing of this article is that using App Engine for Java for scalable, data-intensive Java application development, today, is not for the timid or conservative. It's more like diving into the deep end of the pool: There's not a lifeguard in sight, and it's up to you whether your project sinks or swims.