code: private void handleSerialFactory()
      {
  
          String serialProvider = _externalContext.getInitParameter(StateUtils.SERIAL_FACTORY);
          SerialFactory serialFactory = null;
  
          if (serialProvider == null)
          {
              serialFactory = new DefaultSerialFactory();
          }
          else
          {
              try
              {
                  serialFactory = (SerialFactory) ClassUtils.newInstance(serialProvider);
  
              }
              catch (ClassCastException e)
              {
                  log.log(Level.SEVERE, "Make sure '" + serialProvider + "' implements the correct interface", e);
              }
              catch (Exception e)
              {
                  log.log(Level.SEVERE, "", e);
              }
              finally
              {
                  if (serialFactory == null)
                  {
                      serialFactory = new DefaultSerialFactory();
                      log.severe("Using default serialization provider");
                  }
              }
  
          }
  
          log.info("Serialization provider : " + serialFactory.getClass());
          _externalContext.getApplicationMap().put(StateUtils.SERIAL_FACTORY, serialFactory);
      }
docs: /*
  private String getLifecycleId()
  {
  String id = _externalContext.getInitParameter(FacesServlet.LIFECYCLE_ID_ATTR);
  
  if (id != null)
  {
  return id;
  }
  
  return LifecycleFactory.DEFAULT_LIFECYCLE;
  }