A rich API Used for programming of single-page Web applications and Web applications synchronicity. Models and Views - The single most important thing that Backbone can help you with is keeping your business logic separate from your user interface. Collections - A Collection helps you deal with a group of related models, handling the loading and saving of new models to the server and providing helper functions for performing aggregations or computations against a list of models. View Rendering - Each View manages the rendering and user interaction within its own DOM element. If you're strict about not allowing views to reach outside of themselves, it helps keep your interface flexible — allowing views to be rendered in isolation in any place where they might be needed. Routing with URLs - In rich web applications, we still want to provide linkable, bookmarkable, and shareable URLs to meaningful locations within an app. Use the Router to update the browser URL whenever the user reaches a new "place" in your app that they might want to bookmark or share. Conversely, the Router detects changes to the URL — say, pressing the "Back" button — and can tell your application exactly where you are now.

* The GWT SDK provides a set of core Java APIs and Widgets. These allow you to write AJAX applications in Java and then compile the source to highly optimized JavaScript that runs across all browsers, including mobile browsers for Android and the iPhone. * Constructing AJAX applications in this manner is more productive thanks to a higher level of abstraction on top of common concepts like DOM manipulation and XHR communication. * You can debug AJAX applications in your favorite IDE just like you would a desktop application, and in your favorite browser just like you would if you were coding JavaScript. The GWT developer plugin spans the gap between Java bytecode in the debugger and the browser’s JavaScript. * GWT contains two powerful tools for creating optimized web applications. The GWT compiler performs comprehensive optimizations across your codebase — in-lining methods, removing dead code, optimizing strings, and more. By setting split-points in the code, it can also segment your download into multiple JavaScript fragments, splitting up large applications for faster startup time. * When you’re ready to deploy, GWT compiles your Java source code into optimized, stand-alone JavaScript files that automatically run on all major browsers, as well as mobile browsers for Android and the iPhone.