We had new kitchen cabinets and new granite counter tops installed about a year ago...The granite installer told our remodeler to put a half inch plywood deck down on the tops of the base cabinets...then the Granite counter was glued down to the plywood deck...and it is true that the granite is very heavy so not much adhesive was needed ...just enough to keep it from shifting if at all possible for the granite.
I was home to watch the granite counter installed..it was quite impressive! Hope thhis helps.