code: protected void removeFacesListener(FacesListener listener) {
  
          if (listener == null) {
              throw new NullPointerException();
          }
  
          if (listeners != null) {
              listeners.remove(listener);
          }
  
      }
docs: <p>Remove the specified {@link FacesListener} from the set of listeners
  registered to receive event notifications from this {@link UIComponent}.
  
  @param listener The {@link FacesListener} to be deregistered
  @throws NullPointerException if <code>listener</code>
  is <code>null</code>