In Java, what is MVC design pattern? How is the MVC design pattern used in Struts framework?

MVC Pattern stands for Model-View-Controller Pattern. This pattern is used to separate application's concerns.

Model - Model represents an object or JAVA POJO carrying data. It can also have logic to update controller if its data changes.

View - View represents the visualization of the data that model contains.

Controller - Controller acts on both Model and view. It controls the data flow into model object and updates the view whenever data changes. It keeps View and Model separate.

Struts is a framework of open-source software that can help you build Web applications quickly and easily. It relies on standard technologies such as Java beans, Java servlets, JavaServer Pages (JSP), and XML. Struts encourages application architectures based on the Model2 approach, which is basically the same as the model-view-controller (MVC) design pattern.

Using Struts to create a complex Web application can help make the application more maintainable. The application is easier to debug, easier to extend, and easier to understand.

The centerpiece of Struts is its MVC-style controller, which integrates with other technologies that provide the model and the view. For the model, Struts can interact with standard data access technologies such as JDBC and EJB, as well as many third-party packages such as Hibernate, iBATIS, or Object Relational Bridge. For the view, Struts works well with JSP, including the JSP Standard Tag Library (JSTL) and JavaServer Faces (JSF), as well as Velocity Templates, XSLT, and other presentation systems.