A DESCRIPTION OF THE PROBLEM :
In example of java.util.stream.Collectors (both toMap() and toConcurrentMap() methods), the class name Function.identity() is mistyped as Functions.identity().

There is only java.util.function.Function interface, no Functions interface in core JDK.


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