There are many popular established web frameworks around us for several years and there are many more taking shape. A common list of popular web frameworks are
From Ruby world : Ruby on Rails
Python : DJango, Turbo gears
Java : enormous … Wicket , Pivot , Tapestry , Stripes , Scooter, JSF , Struts, Java FX
C# : .net and silver light
Scala : Lift
Google : GWT
I personally love to work on Rails and DJango as they are open source, flexible, abstract the internal complexity from the developer and guarded by strong communities and based on Dynamic languages. Though these frameworks simple but becomes more complex when we need to scale up and we need to learn a new jargons and way to code. Of course we need to learn the base languages on which these frame works have been built. They are extremely powerful web frame works but we need to master the craft. If I am a python or ruby guy then I would not think twice before I could use them.
I was looking very recently for one of my project to work on a simple java frame work where I need not to learn many new jargons and concepts and gone thru few of them and not much help as each one has their own yards.
I found a new Vaadin framework which is very simple to learn and gone thru their documentation and its pretty amazing and started working and it works.
The following are the features which fascinates me about Vaadin :
Enables creating Rich Internet Applications fast.
It is built on Java which most of the developers familiar with and licensed under apache.
The frame work is more like swing so it is very nearer to hearts of desktop guys.
Does not need a plug in like Java FX or flex. So it is browser agnostic.
Built on GWT based widgets. This helps in extending to write custom user controls and support from Google. Also gets App engine support is big plus.
Eclipse plugin support is available. Now a days this is very basic however.
There are many pre built UI controls ready to use with most commonly used features. Decent implementation.
The default skinning looks good. Provides user modified theaming using CSS.
Integrating Vaadin with other popular frame works from java world like Spring and hibernate.
The frame work is well documented comes with on line demo and the source code and a Book.
Backed by company called IT mills and comes with a long heritage. The project started on year 2000.
If you have time do stop by www.vaadin.com.