Demos are great they illustrate the power of a product and provide a great insight into the functionality a set of technologies can provide.  This demo page will highlight excellent online demos and third power libraries that turn fast GWT applications into furious ones.

GWT-Platform (GWTP) -
GWT makes programming web apps look deceptively simple. However, building an efficient application that you can easily expand is far from being a trivial task. A good way to start your project on a strong footing is to adhere to a well-established architecture molded around GWT's best features.

GWTP (goo-teepee for short), is a collection of components that build up such an architecture. You can pick the components you need or build your new project from the ground up using the entire package. No matter which approach you choose, GWT optimized compilation will make sure only the features you really use are part of your final code. Read on for more details or get started right away!

Smart GWT -
Smart GWT is a GWT based framework that allows you to not only utilize its comprehensive widget library for your application UI, but also tie these widgets in with your server-side for data management. Smart GWT is based on the powerful and mature SmartClient library.

Vaadin -
What Is Easy With Vaadin?
  •     Create Rich Internet Applications fast - With Vaadin, you create web applications in minutes. A few lines of Java code and Vaadin takes care of the rest. No complex configurations, no JavaScript.
  •     Code on the server side - With Vaadin, you run your applications on a server, with the full power and flexibility of Java.
  •    Wide browser support - Built on GWT-based widgets, Vaadin applications support all Ajax-capable browsers, with no plugins.
  •    Stunning Web Applications - The look and feel makes a difference. Vaadin comes with great-looking components and easy use of themes.
  •     Secure Applications - The server-side architecture ensures that your application code is hidden from the world.
  •     Maintainable Applications - Pure Java gives you the power to build applications that can be easily extended and maintained.