Jeanne,
Very fast answer! Sorry for not being specific: I am studying with this - very good - book:
OCP Oracle Certified Professional
Java SE 8 Programmer II STUDY GUIDE
EXAM 1Z0-809
Jeanne Boyarsky and Scott Selikoff
SYBEX A Wiley Brand
Copyright 2016
ISBN: 978-1-119-06790-0
and the supposed typo is in Chapter 2 - Design
Patterns and Principles,
Defining a Functional Interface,
p. 54,
second line of the second to last paragraph