code: private static void validate(String name, Collection<Geometry> geometries, int extent) {
          if (name == null) {
              throw new IllegalArgumentException("layer name is null");
          }
          if (geometries == null) {
              throw new IllegalArgumentException("geometry collection is null");
          }
          if (extent <= 0) {
              throw new IllegalArgumentException("extent is less than or equal to 0");
          }
      }
docs: Validate the JtsLayer.
  
  @param name mvt layer name
  @param geometries geometries in the tile
  @throws IllegalArgumentException when {@code name} or {@code geometries} are null