code: protected void addToNonSingletonListeners(final Object bean) {
          if( logger.isDebugEnabled() )
              logger.debug( "Adding Authentication/LoginAware bean to list of non-singleton listeners: bean='" + bean );
  
          nonSingletonListeners.add( new WeakReference( bean ) );
      }
docs: Add a non-singleton bean instance to our list for later notification.
  @param bean