code: public boolean has() {
  
  		boolean exists = false;
  		try {
  			exists = has(EXTENSION_NAME, null, null)
  					&& contentsIdDao.isTableExists();
  		} catch (SQLException e) {
  			throw new GeoPackageException(
  					"Failed to check for contents id for GeoPackage: "
  							+ geoPackage.getName(), e);
  		}
  
  		return exists;
  	}
docs: Determine if the GeoPackage has the extension
  
  @return true if has extension