code: public static Point getCircumCenter(Geometry geometry) {
          if(geometry == null || geometry.getNumPoints() == 0) {
              return null;
          }
          return geometry.getFactory().createPoint(new MinimumBoundingCircle(geometry).getCentre());
      }
docs: Compute the minimum bounding circle center of a geometry
  @param geometry Any geometry
  @return Minimum bounding circle center point