I know there is a pretty high number of programmers who haven't tried to dable GWT yet because out of the box, the back end is java only. PHP developers rejoice!
_Unlike most of the other frameworks, GwtPHP is a framework for both client and server part. In GwtPHP you don’t need to hack JavaScript, you work with modern, object oriented languages. User interface (client) is programmed in Java, then compiled by Google Web Toolkit (GWT) to browser-dependent JavaScript. Server part uses PHP 5. _
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