In this chapter, we will cover several aspects of Facelets templating and some related aspects.

JSF is defined as a component-based application development framework. When we say Facelets, we mean friendly page development, reusability of code, templating, composition components, custom logic tags, expression functions, high-performance rendering, optimized compilation time, and so on. But what actually is Facelets? Well, Facelets represents a VDL (View Declaration Language), and initially, it was created as an alternative to JSP. During JSF 1.1 and 1.2, this view handler can be used only after a separate download and configuration, while JSP was the default view handler. Things started to change with JSF 2.0, when the mismatch between JSF and JSP allowed Facelets to become the standard and default VDL, while JSP was deprecated. Starting with JSF 2.2, this concept was seriously fortified and Facelets was boosted with new features and capabilities.