Struts is an open source MVC framework that makes it easier to develop and maintain Java web applications by providing common functionality out of the box and enforcing standardized patterns, reducing the need to write boilerplate code and helping developers focus on business logic. The framework handles common tasks like request processing, validation, and view resolution while providing features like tag libraries, internationalization support, and annotation-based configuration. Struts uses the model-view-controller architectural pattern and is based on technologies like servlets, JSPs, and Java beans.