Can we use Google Web Toolkit (GWT) and Yahoo! User Interface (YUI) to develop JavaScript and AJAX code in Java? Which one is better? Or is there any other better framework than these two?
As GWT auto-generates the pages, I doubt it can be used with anything else. Unless there are some hooks that they've added to allow this, that is. I wouldn't know as it is not a tool I'd consider using.
Sure there are plenty of JavaScript frameworks and libraries, each with their own advantages and drawbacks. There is no best one.