The JavaServer Faces lifecycle spans all of the execute and render
processes of an application. It is also possible to process and render
only parts of an application, such as a single component. For example,
the JavaServer Faces Ajax framework can generate requests containing
information on which particular component may be processed and which
particular component may be rendered back to the client.
Once such a partial request enters the JavaServer Faces lifecycle, the
information is identified and processed by a
javax.faces.context.PartialViewContext object. The JavaServer Faces
lifecycle is still aware of such Ajax requests and modifies the
component tree accordingly.