A DESCRIPTION OF THE PROBLEM :
Java Doc for Collectors.averagingInt states the following:
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Returns:
a Collector that produces the sum of a derived property
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But it returns "arithmetic mean of an integer-valued function applied to the input elements"
The same issue for averagingLong and averagingDouble

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Returns:
a Collector that produces the arithmetic mean of an integer-valued function applied to the input elements
ACTUAL -
Returns:
a Collector that produces the sum of a derived property

URL OF FAULTY DOCUMENTATION :
https://docs.oracle.com/javase/8/docs/api/java/util/stream/Collectors.html#averagingInt-java.util.function.ToIntFunction-