From an application developer's point of view, a JSF application consists of a series of XHTML pages that contain custom JSF tags, one or more CDI named beans, and an optional configuration file named faces-config.xml.
Note
The faces-config.xml file was required in JSF 1.x; however, in JSF 2.0, some conventions were introduced to reduce the need for configuration. Additionally, a number of JSF configurations can be specified using annotations, reducing and, in some cases, eliminating the need for this XML configuration file.
Previous versions of JSF required JSF managed beans to implement server-side functionalities. For backward compatibility, JSF managed beans are still supported; however, CDI named beans are preferred in modern JSF applications.