I like Vaadin - Java web framework created by Finnish guys from ITMill.
Vaadin homepage: http://vaadin.com
This is demo web application built with Vaadin+Maven which performs search files on server.
It was really easy to create it!
All you need is to include Vaadin depenency to your pom.xml and create class that extends com.vaadin.Application. No any XMLs, jsp etc.
Full source code:
Short overview of Vaadin: http://www.streamhead.com/vaadin-promote-great-gwt-toolkit/
Видео: Илья Ливенсон – Наши люди в Омане