STRUTS INTERVIEW QUESTIONS

Q.What is Action Class. What are the methods in Action class?

An Action is an adapter between the contents of an incoming HTTP request and the corresponding business logic that should be executed to process this request. The controller (RequestProcessor) will select an appropriate Action for each request, create an instance (if necessary), and call the execute method. Actions must be programmed in a thread-safe manner, because the controller will share the same instance for multiple simultaneous requests. This means you should design with the following items in mind: Instance and static variables MUST NOT be used to store information related to the state of a particular request. They MAY be used to share global resources across requests for the same action.

Access to other resources (JavaBeans, session variables, etc.) MUST be synchronized if those resources require protection. (Generally, however, resource classes should be designed to provide their own protection where necessary. When an Action instance is first created, the controller will call setServlet with a non-null argument to identify the servlet instance to which this Action is attached. When the servlet is to be shut down (or restarted), the setServlet method will be called with a null argument, which can be used to clean up any allocated resources in use by this Action.


Q.What is Action Class? What are the methods in Action class?

An Action class is some thing like an adapter between the contents of an incoming HTTP request and the corresponding business logic that should be executed to process this request. The controller (RequestProcessor) will select an appropriate Action for each request, create an instance (if necessary), and call the execute method. Struts Action class is a unit of logic. It is where a call to business function is made. In short the Action class acts like a bridge between client side(user action) and business operation(on server. Some of the impotant methods of Action class are, execute()generateToken() resetToken() getServlet()


Q.What is the use of ActionForm class, Describe it's Life Cycle?

ActionForm class is used to capture user-input data from an HTML form and transfer it to the Action Class. ActionForm plays the role of Transport Vehicle between the presentation Tire & Business Tier.Life Cycle :1. Request received by Controller2. Create or recycle ActionForm3. Call reset()4. store ActionForm in proper scope5. populate ActionForm from Request6. Validate the ActionForm7. If errors found then forward back to input attribute page(configured in Action mapping in struts-config.xml) with ActionForm in scope. If no errors found then call execute() with the ActionForm.