Which Design patterns are used in Struts framework ?

Design patterns used in Struts 1x

• MVC: Struts framework is based on Model 2 MVC pattern.
• FrontController : Provides a centralized controller (ActionServlet) for managing the handling of requests.
• Command pattern: Struts controller uses the Command design pattern.
• Adapter pattern: Action classes use the Adapter design pattern.
• Template pattern: The process() method of the RequestProcessor uses the Template method design pattern.
• Composite View: Used in Struts Tiles.
• Value Object (VO) / Context object: Form Beans that encapsulate the values entered on a form.
• Chain of Responsibility pattern (CoR): Request Processor  is composed using commons chain, which is an implementation of CoR pattern.
• Dispatcher View: Using ActionMapping to forward the flow to the View after performing some business logic from the action class.
• View Helper: Encapsulates logic that is not related to presentation formatting into Helper components.
• Service to Worker: Combines a Dispatcher component with the Front Controller and View Helper patterns.
• Synchronizer Token: This strategy addresses the problem of duplicate form submissions. Uses this strategy to control direct browser access to certain pages.

• Struts 2 uses Inversion of Control (IoC) pattern also known as dependency injection.