Struts Interview Questions

What is Struts?

Struts provides its own Controller component and integrates with other technologies to provide the Model and the View. For the Model, Struts can interact with standard data access technologies, like JDBC and EJB, as well as most any third-party packages, like Hibernate, iBATIS, or Object Relational Bridge. For the View, Struts works well with JavaServer Pages, including JSTL and JSF, as well as Velocity Templates, XSLT, and other presentation systems.

The Struts framework provides the invisible underpinnings every professional web application needs to survive. Struts helps you create an extensible development environment for your application, based on published standards and proven design patterns.

What is ActionServlet?
The class org.apache.struts.action.ActionServlet is the called the ActionServlet. In the the Jakarta Struts Framework this class plays the role of controller. All the requests to the server goes through the controller. Controller is responsible for handling all the requests.

What is Action Class?

The Action Class is part of the Model and is a wrapper around the business logic. The purpose of Action Class is to translate the HttpServletRequest to the business logic. To use the Action, we need to Subclass and overwrite the execute() method. In the Action Class all the database/business processing are done.
It is advisable to perform all the database related stuffs in the Action Class. The ActionServlet (commad) passes the parameterized class to Action Form using the execute() method.
The return type of the execute method is ActionForward which is used by the Struts Framework to forward the request to the file as per the value of the returned ActionForward object.

What is ActionForm?
An ActionForm is a JavaBean that extends org.apache.struts.action.ActionForm. ActionForm maintains the session state for web application and the ActionForm object is automatically populated on the server side with data entered from a form on the client side.

What is Struts Validator Framework?

Struts Framework provides the functionality to validate the form data. It can be use to validate the data on the users browser as well as on the server side.
Struts Framework emits the java scripts and it can be used validate the form data on the client browser. Server side validation of form can be accomplished by sub classing your From Bean with DynaValidatorForm class.
The Validator framework was developed by David Winterfeldt as third-party add-on to Struts. Now the Validator framework is a part of Jakarta Commons project and it can be used with or without Struts. The Validator framework comes integrated with the Struts Framework and can be used without doing any extra settings.
What is the difference between Struts 1.0 and Struts 1.1?
Struts 1.1 has method execute in action class where as Struts 1.0 contains performexecute() method
The new features added to Struts 1.1 are 1. RequestProcessor class 2. Method perform() replaced by execute() in Struts base Action Class 3. Changes to web.xml and struts-config.xml4.Declarative exception handling5.Dynamic ActionForms6.Plug-ins7.Multiple Application Modules8.Nested Tags9.The Struts Validator10.Change to the ORO package11.Change to Commons logging12.Removal of Admin actions13. Deprecation of the GenericDataSource.

Give the Details of XML files used in Validator Framework?
The Validator Framework uses two XML configuration files validator-rules.xml and validation.xml. The validator-rules.xml defines the standard validation routines, these are reusable and used in validation.xml. to define the form specific validations. The validation.xml defines the validations applied to a form bean.

How to get data from the velocity page in a action class?
We can get the values in the action classes by using data.getParameter(\"variable name defined in the velocity page\");

What is the difference between ActionForm and DynaActionForm?
There is no need to write actionform class for the DynaActionForm and all the variables related to the actionform class will be specified in the struts-config.xml where as we have to create Actionform class with getter and setter methods which are to be populated from the form.

1. In DynaActionForm Can't create resect() and validate() methods.
2. If u have any change in DynaActionForm U change only in property files in Struts-config.xml file only

Diffrence b/w Struts1.x and Struts2.x?

• The Struts2.x there is no loginform.
• The Struts-config.xml file replaced with Struts.xml.
• A new property file struts.properties is introduced.
• Struts 1 jar files are replaced to struts 2 JAR files.
• Removeelemetns as no form-bean mapping is required.
• Replaceelement with element.

What is major diffrence struts and spring?

There's no need of a formcontroller if you donot hava a form.Any object can be used as a command or form object it is not required to implement an interface or derive from a base class.

Spring framwork provids proper test invironment than struts,which is important for projects developed using test-driven methodologies.