Not sure whether it is a bug, so just fire a question.

I have following map/reduce functions defined:

m = function()

{ emit("totalClickCount", this.clickCount); }

r = function(key, values)

{ return Array.sum(values); }

If I run everything in mongodb console, I can get result as I expected:

{ "_id" : "totalClickCount", "value" : 2 }

, here value is an integer; but if I use mongodb-java-driver to do exactly the same thing, it returns double instead of integer for "value". Also, I tried to query the temporary collection directly in mongodb console, and it is integer as well.

I tried to debug, and saw that for returned BSON stream, data type was "NUMBER" which means a floating point according to BSON's spec, so seems that mongodb-java-driver is correct. But why does server return a double type?