code: public GeometryColumns getGeometryColumns() {
  		GeometryColumns result = null;
  		if (geometryColumns.size() > 1) {
  			// This shouldn't happen with the unique table name constraint on
  			// geometry columns
  			throw new GeoPackageException(
  					"Unexpected state. More than one GeometryColumn has a foreign key to the Contents. Count: "
  							+ geometryColumns.size());
  		} else if (geometryColumns.size() == 1) {
  			CloseableIterator<GeometryColumns> iterator = geometryColumns
  					.closeableIterator();
  			try {
  				result = iterator.next();
  			} finally {
  				try {
  					iterator.close();
  				} catch (IOException e) {
  					throw new GeoPackageException(
  							"Failed to close the Geometry Columns iterator", e);
  				}
  			}
  		}
  		return result;
  	}
docs: Get the Geometry Columns, should only return one or no value
  
  @return geometry columns