FULL PRODUCT VERSION :
java version "1.8.0_77"
Java(TM) SE Runtime Environment (build 1.8.0_77-b03)
Java HotSpot(TM) 64-Bit Server VM (build 25.77-b03, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Windows 10 anniversary edition

A DESCRIPTION OF THE PROBLEM :
In the Javadoc of java.util.stream.Collectors, methods

toMap(Function<? super T,? extends K> keyMapper,
                                                    Function<? super T,? extends U> valueMapper)

toConcurrentMap(Function<? super T,? extends K> keyMapper, Function<? super T,? extends U> valueMapper)

code samples are provided referencing non-existent method Functions.identity().
This should be Function.identity().


REGRESSION. Last worked in version 8u77

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Check provided javadoc in JDK release / check web javadoc @ docs.oracle.com/javase/8/docs/api/java/util/stream/Collectors.html


REPRODUCIBILITY :
This bug can be reproduced always.