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Structs Interview Questions and Answers
What is Struts?
Struts is a web page development framework and an open source software
that helps developers build web applications quickly and easily. Struts
combines Java Servlets, Java Server Pages, custom tags, and message
resources into a unified framework. It is a cooperative, synergistic
platform, suitable for development teams, independent developers, and
everyone between.
How is the MVC design pattern used in Struts framework?
In the MVC design pattern, application flow is mediated by a central
Controller. The Controller delegates requests to an appropriate handler.
The handlers are tied to a Model, and each handler acts as an adapter
between the request and the Model. The Model represents, or
encapsulates, an application's business logic or state. Control is
usually then forwarded back through the Controller to the appropriate
View. The forwarding can be determined by consulting a set of mappings,
usually loaded from a database or configuration file. This provides a
loose coupling between the View and Model, which can make an application
significantly easier to create and maintain.
Controller--Servlet controller which supplied by Struts itself; View ---
what you can see on the screen, a JSP page and presentation components;
Model --- System state and a business logic JavaBeans.
Who makes the Struts?
Struts is hosted by the Apache Software Foundation(ASF) as part of its
Jakarta project, like Tomcat, Ant and Velocity.
Why it called Struts?
Because the designers want to remind us of the invisible underpinnings
that hold up our houses, buildings, bridges, and ourselves when we are
on stilts. This excellent description of Struts reflect the role the
Struts plays in developing web applications.
Do we need to pay the Struts if being used in commercial purpose?
No. Struts is available for commercial use at no charge under the Apache
Software License. You can also integrate the Struts components into your
own framework just as if they were written in house without any red
tape, fees, or other hassles.
What are the core classes of Struts?
Action, ActionForm, ActionServlet, ActionMapping, ActionForward are
basic classes of Structs.
What is the design role played by Struts?
The role played by Structs is controller in Model/View/Controller(MVC)
style. The View is played by JSP and Model is played by JDBC or generic
data source classes. The Struts controller is a set of programmable
components that allow developers to define exactly how the application
interacts with the user.
How Struts control data flow?
Struts implements the MVC/Layers pattern through the use of
ActionForwards and ActionMappings to keep control-flow decisions out of
presentation layer.
What configuration files are used in Struts?
ApplicationResources.properties
struts-config.xml
These two files are used to bridge the gap between the Controller and
the Model.
What helpers in the form of JSP pages are provided in Struts
framework?
--struts-html.tld
--struts-bean.tld
--struts-logic.tld
Is Struts efficient?
The Struts is not only thread-safe but thread-dependent(instantiates
each Action once and allows other requests to be threaded through the
original object.
ActionForm beans minimize subclass code and shorten subclass hierarchies
The Struts tag libraries provide general-purpose functionality
The Struts components are reusable by the application
The Struts localization strategies reduce the need for redundant JSPs
The Struts is designed with an open architecture--subclass available
The Struts is lightweight (5 core packages, 5 tag libraries)
The Struts is open source and well documented (code to be examined
easily)
The Struts is model neutral
How you will enable front-end validation based on the xml in
validation.xml?
The < html:javascript > tag to allow front-end validation based on the
xml in validation.xml. For example the code: < html:javascript formName=logonForm
dynamicJavascript=true staticJavascript=true / > generates the client
side java script for the form logonForm as defined in the validation.xml
file. The < html:javascript > when added in the jsp file generates the
client site validation script.
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.
How you will make available any Message Resources Definitions file
to the Struts Framework Environment?
Message Resources Definitions file are simple .properties files and
these files contains the messages that can be used in the struts
project. Message Resources Definitions files can be added to the struts-config.xml
file through < message-resources / > tag. Example: < message-resources
parameter= MessageResources / >
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