In the preceding markup, we added a <h:selectOneMenu> tag and a command
button to allow the user to select the desired theme.
A very nice JSF feature is the ability to easily write custom JSF components. With JSF
2, creating a custom component involves little more than creating the markup for
it, without any Java code or configuration. Since custom components are typically
composed of other JSF components, they are referred to as composite components.
We can generate a composite component by going to File | New File , selecting the
JavaServer Faces category, and selecting the JSF Composite Component file type.