elasticsearch/elasticsearch — pull request #7275 by jpountz (2014-08-14 10:11:46+00:00)
Title: Aggregations: Make the list of buckets for terms and histogram returned as a java.util.List.

The terms and histogram aggregations always have an order. So it would make the
response easier to consume to return the buckets as a list instead of a
collection in order to make it easier to do things like getting the first/last
buckets.