JavaServer Faces (JSF) is a Java-based Web application framework intended to simplify development of user interfaces for Java EE applications. Unlike request-driven MVC web frameworks, JSF uses a component-based approach. The state of UI components is saved when the client requests a new page and restored when the response is returned. Out of the box, JSF uses JavaServer Pages (JSP) for its display technology, but can also accommodate other technologies (such as XUL and Facelets). JSF includes:

• A set of APIs for representing user interface (UI) components and managing their state, handling events and input validation, converting values, defining page navigation, and supporting internationalization and accessibility
• A default set of UI components
• Two JavaServer Pages (JSP) custom tag libraries for expressing a JavaServer Faces interface within a JSP page.
• A server-side event model
• State management
• Managed Beans (JavaBeans created with dependency injection)
• Unified Expression Language for both JSP 2.0 and JSF 1.2

The JSF specification was developed under the Java Community Process as JSR 127, which defined JSF 1.0 and 1.1, and JSR 252 which defined JSF 1.2. Upcoming JSF 2.0 is being developed as JSR 314.