code: private static Point2D computePointsCentroid(MultiPoint multiPoint)
      {
          double xSum = 0;
          double ySum = 0;
          int pointCount = multiPoint.getPointCount();
          Point2D point2D = new Point2D();
          for (int i = 0; i < pointCount; i++) {
              multiPoint.getXY(i, point2D);
              xSum += point2D.x;
              ySum += point2D.y;
          }
          return new Point2D(xSum / pointCount, ySum / pointCount);
      }
docs: Points centroid is arithmetic mean of the input points