Define MVC pattern.

MVC pattern differenciates all the 3 aspects of application in 3 difft tiers.

Modal
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- Holds the business logic of the application.
- holds data sent betw. difft. tiers like JSP to servlet and hadler classes.

View
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- handles presentation tier of the application.
- handles presentation logic, client side validation.
- e.g. HTML, JSP

Controller
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- handles the flow of the application
- e.g. Servlets, Action Class in Struts, ActionServlet is using struts-config.xml as front controller to handle each request and redirect it to appropriate destination.

Advantages
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- Increases modularity of the application.
- Increases Maintainability of the application.