Hello,
As discussed here
https://coderanch.com/t/729174/certification/Sybex-Chapter-page, there is an issue in the first chapter saying that single-file command can rely only on JDK-provided classes.
That issue was added to OCP 11 part 1 errata (
https://www.selikoff.net/ocp11-1/), but is missing from OCP 11 Complete errata (
https://www.selikoff.net/ocp11-complete/).
(from OCP 11 Complete from Wiley Publishing)