code: public void close() {
  		if (dbEnv != null) {
  			// closing dbs
  			iidToIdDB.close();
  			idToIidDB.close();
  			if (useGeolocation) {
  				iidToGeolocationDB.close();
  			}
  			if (useMetaData) {
  				iidToMetadataDB.close();
  			}
  			closeInternal();
  			dbEnv.close(); // closing env
  		} else {
  			System.out.println("BDB environment is null!");
  		}
  	}
docs: This method closes the open BDB environment and databases.