difference between Struts 1.x and Struts 2.x

It's a totally different web framework... Struts2 is basically the old Webwork.

Some differences:

• Struts2 works with POJOs, no more ActionForms. All attributes from the requests are populated in "standard" Java classes.
• Struts2 actions are not coupled with the Servlet API, they do not receive HttpServletRequest and HttpServletResponse as parameters. Also, they are stateful, (Struts 1 actions were stateless).
• Struts2 have a lot of enhancements like the Interceptor API, plus lots of integrations.
• Configuration is totally different.