The JSF specification defines a View Declaration Language (VDL) to render the output of the pages. In JSF 1.0, this was JavaServer Pages; but in JSF 2.0, the VDL was changed to Facelets by default. Facelets are the default view handler for JSF 2.0 and are defined as XHTML files.

Facelets can be used in a templating situation. A Facelets file can reference a master template as a composition, and the view can provide the content that will look like a cookie cutter being supplied to the template. A Facelet that utilizes a reference template is known as a template client. The placeholder content in the template client will override the default content in the master template. In this way, Facelets can be reused in order to share the content. The template clients may become master templates and thus, a hierarchy of views can be derived.

Facelets also provide reuse by the custom tags. It is possible for engineers to write their own custom tags through the XHTML files and metadata. The designer...