A DESCRIPTION OF THE PROBLEM :
Collector / finisher method

In the description of the finisher method, there is a misstype:

"If the characteristic IDENTITY_TRANSFORM is set,"

 IDENTITY_TRANSFORM => in the enum this is IDENTITY_FINISH

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
IDENTITY_FINISH
ACTUAL -
 IDENTITY_TRANSFORM

URL OF FAULTY DOCUMENTATION :
https://docs.oracle.com/javase/8/docs/api/index.html?java/util/stream/Collectors.html