What are JSF components ?

JavaServer Faces' User-Interface Components The true power of JavaServer Faces lies in its user-interface component model where applications are merely built from collections of components that can render themselves in diverse ways for multiple client types. Vaguely similar to other proprietary technologies such ASP.Net, JSF's UI Component model technology offers unprecendented productivity by allowing the developer to construct Web user interfaces using pre-built user-interface (UI) Components as opposed to having to construct the user interface entirely from scratch. JSF UI Components come in many forms and can be as simple as an outputLabel which simply displays text or as complex as a dataTable which can represent a tabular data from collections of data such as from a database table. The JavaServer Faces specification provides a set of base UI Components in its Reference Implementation which are very useful on their own. These include two libraries of components such as the "HTML" component library which largely mirrors the standard HTML input elements along with a "Core" library which aids in common application development tasks such as internationalization, and validating/converting input data. In addition to providing a base library of UI Components, the JSF API offers the ability to extend and create custom JSF UI Components providing additional functionality above and beyond the base components. Additional User-Interface Component Libraries Because of the richness and flexibility of the JSF API, many Java developers are beginning to create new JSF Component libraries and implementations. Oracle's ADF Faces is a fully compliant JSF component library which offers a broad set of enhanced UI Components for JSF application development. These include multiple renderers per client type, advanced tables, color and date pickers along with a host of general components such as menus, command buttons, shuttle choosers and progress meters.