A DESCRIPTION OF THE PROBLEM :
The documentation makes repeated reference to "Functions.identity()" in code samples, e.g.:

     Map<Student, Double> studentToGPA
         students.stream().collect(toMap(Functions.identity(),
                                         student -> computeGPA(student)));
 
Such a class does not exist. It should read "Function.identity()".


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Function.identity()
ACTUAL -
Functions.identity()

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