1)Put struts.xml file inside /WEB-INF/classes/

2)Put validation.xml inside /WEB-INF/

3)The controller is implemented by a java servlet, this servlet is centralized point of control for the web application. In struts framework the controller responsibilities are implemented by several different components like

The ActionServlet Class
The RequestProcessor Class
The Action Class

ActionServlet: Struts ActionServlet handles all the request made by the web browsers to a given mapping. ActionServlet is the central component of the Struts controller. This servlet extends the HttpServlet. This servlet basically performs two important things. First is : When the container gets start, it reads the Struts Configuration files and loads it into memory in the init() method. You will know more about the Struts Configuration files below. Second point is: It intercepts the HTTP request in the doGet() and doPost() method and handles it appropriately.

RequestProcessor:RequestProcessor process the request from the controller. You can sublass the RequestProcessor with your own version and modify how the request is processed. Once the controller receives a client request, it delegates the handling of the request to a helper class. This helper knows how to execute the business operation associated with the requested action.

Action: In the Struts framework,Action class acts as a bridge between a client-side user action and business operation. The Action class decouples the client request from the business model. This decoupling allows for more than one-to-one mapping between the user request and an action. The Action class also can perform other functions such as authorization, logging before invoking business operation. the Struts Action class contains several methods, but most important method is the execute() method.