struts interview questions

Ques: 28 What is an ActionMapping?

Ans: An ActionMapping object describes an Action instance to the ActionServlet. It represents the information that uniquely defines an instance of a particular action class. The values defined by an ActionMapping object are what make a particular <action> definition unique.

The ActionMapping object also provides useful information to the Action.execute() method, giving an Action object the ability to alter its behaviour based on the values describing a particular ActionMapping instance. The signature of the Action.execute() method:

public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response){//some code here}

Ques: 29 How will you create your own ActionMapping?

Ans: To create your own ActionMapping extention, you have to perform the following steps:

  * Create a class that extends the org.apache.struts.action.ActionMapping class.

  * Define the additional properties that will be used to describe your Action objects.

  * Call the super() method, which calls the ActionMapping's default constructor at the beginning of your action mapping's contructor.

  * Define matching setters and getters that can be used to modify and retrieve the values of the defined properties.

Ques: 30 What are the extensions of the ActionMapping provided by the struts?

Ans: The struts framework provides two extended ActionMapping classes:  

   * org.apache.struts.action.SessionActionMapping

   * org.apache.struts.action.RequestActionMapping.

Ques: 31 What are the two i18n components of a Struts Application?

Ans: The tow main components packaged with the Struts framework for internationalization of your Struts application are:

  * Message class that references a resource bundle containing Locale-dependent string and managed by the application Contorller.

  * JSP custom tag, <bean-message/>, which is used in the view layer to present the actual string managed by the Contorller.

Ques: 32 Give name of the error management classes provided by the Struts framework?

Ans: The Struts framework provides two error management classes:

  * ActionError

  * ActionErrors

Ques: 33 What is the difference between the ActionError and ActionErrors class provided by the Struts Framework?

Ans: The org.apache.struts.action.ActionError class extends the org.apache.struts.action.ActionMessage class and reresents the single error message. The key attribute of the ActionError class is used to lookup a resource from the application resource bundle, "Internationalizing your struts application".

The org.apache.struts.action.ActionErrors class extends the org.apache.struts.action.ActionMessage class and represents a collection of ActionError classes. The ActionErrors class is composed of two contructors and a single method that allows you to add an ActionError object to the current collection of ActionErrors.

Ques: 34 What is for <html:errors/> tag provided by Struts specific JSP tag library.

Ans: The <html:errors/> tag is used to display the ActionError objects stored in ActionErrors collection.

Ques: 35 What is the tiles framework in struts?

Ans: The tiles framework turns the concept of jsp:includes inside out. Developers can build pages by assembling reusable Tiles. You can think of Tiles as visual components.

A Tile and a Tile layout can be reused on more than one page. Tiles are other JSP pages or any web resource. Tile layouts dictate how the Tiles will be laid out on the page.

Ques: 36 How will you create a Tile layout view in your struts application?

Ans: To create a TIle layout, you must do the following:

  * Import the Tiles taglib into the JSP by using taglib directive.

  * Use string parameters to display such elements as the title of the page using the tiles:getAsStringTag.

  * Insert the Tiles in the correct regions of the layout using the tiles:insert tag.

  * Pass any needed parameters to the internal Tiles using the sub-tag of tiles:insert called tiles:put.