Just a quick sample of using the af:poll components. A component that enables you to do things in a periodic fashion. For example check if something has changed on the server and update the UI.

A more "modern" approach is to actually use push instead of pull, and ADF Faces will allow you to do that with ADS (here, and here). But the poll still has its place.
It's quite useful for dashboard type of applications where you want periodic updates of the graphs shown on the page.

As you can see it's quite simple to use the tag.
I also show my lazy approach to invoking declarative operations on a data control from a backing bean without manually writing code.