WebWork is a Java web-application development framework. It is built specifically with developer productivity and code simplicity in mind, providing robust support for building reusable UI templates, such as form controls, UI themes, internationalization, dynamic form parameter mapping to JavaBeans, robust client and server side validation, and much more.

Features :
A flexible Validation framework allowing you to decouple validation rules from your action code.
Type Conversion allowing you to easily convert objects from one class to another, solving one of the most tedious efforts when creating web apps.
A powerful Expression Language based on OGNL allowing dynamic object graph traversal and method execution and transparent access to properties from multiple beans using a ValueStack. Webwork also has the ability to use JSTL.
Inversion of Control integration that manages component lifecycle and dependencies without the need to build registry classes that clients must call to obtain a component instance. WebWork recommends Spring for IoC.
Reusable Tags that allow for easy and reusable component-oriented web development using Themes and Templates
Advanced Interceptors that provide for various rich functionality, including preventing multiple form submissions and executing long running queries in the background.
Hierarchical and pluggable support for Internationalization.
Easy integration with third party software including Hibernate, Spring, Sitemesh, and JSTL.
Support for many view technologies such as JSP, FreeMarker, and JasperReports.
Modular Configuration Files using packages and namespaces to manage hundreds of actions.
Advanced AJAX features provided by the ajax theme.