Section 5.5.5: (page 194 US ed; page 166 Global ed)
.reduce(0, (total, count) -> return total + count);
should read
.reduce(0, (total, count) -> total + count);
and (page 195 US ed; page 167 Global ed)
(total, count) -> return total + count
should read
(total, count) -> total + count