AJAX: Selecting the Framework that FitsGWT is a Java-based AJAX framework that lets you write front-end UI components using Java, then use the GWT compiler to convert them into HTML and JavaScript files. GWT's programming model also didn't fit well with our development environment because our team was split between UI developers and back-end Java developers. Also, the generated HTML/JavaScript code would be difficult to change if we had browser issues. Finally, building the application with GWT required us to learn new Java APIs—not good, considering our time and budget constraints.
Source : Picking an Ajax Framework
