The Java Tutorials have been written for JDK 8. Examples and practices described in this page don't take advantage of improvements introduced in later releases.
CapabilitiesTest demonstrates the different buffering capabilities available for the machine on which it is run.
DisplayModeTest shows a Swing application that uses passive rendering. If full-screen exclusive mode is available, it will enter full-screen exclusive mode. If display mode changes are allowed, it allows you to switch between display modes.
MultiBufferTest enters full-screen mode and uses multi-buffering through an active render loop.