code: public static String generateGMLink(Geometry geom, String layerType, int zoom) {
          if (geom == null) {
              return null;
          }
          try {
              LayerType layer = LayerType.valueOf(layerType.toLowerCase());
              Coordinate centre = geom.getEnvelopeInternal().centre();
              StringBuilder sb = new StringBuilder("https://maps.google.com/maps?ll=");
              sb.append(centre.y);
              sb.append(",");
              sb.append(centre.x);
              sb.append("&z=");
              sb.append(zoom);
              sb.append("&t=");
              sb.append(layer.name());
              return sb.toString();
          } catch (IllegalArgumentException ex) {
              throw new IllegalArgumentException("Layer type supported are m (normal  map) , k (satellite), h (hybrid), p (terrain)", ex);
          }
      }
docs: Generate a Google Map link URL based on the center of the bounding box of the input geometry.
  Set the layer type and the zoom level.
  
  @param geom
  @param layerType
  @param zoom
  @return