code: public static void close(
  		final Collection<MasterTriggerRestoreHook<?>> hooks,
  		final Logger log) throws FlinkException {
  
  		for (MasterTriggerRestoreHook<?> hook : hooks) {
  			try {
  				hook.close();
  			}
  			catch (Throwable t) {
  				log.warn("Failed to cleanly close a checkpoint master hook (" + hook.getIdentifier() + ")", t);
  			}
  		}
  	}
docs: Closes the master hooks.
  
  @param hooks The hooks to close
  
  @throws FlinkException Thrown, if the hooks throw an exception.