docs: @SuppressWarnings("unchecked")
  	public void addBeanContextMembershipListener(BeanContextMembershipListener listener)
  	{
  		if (listener == null)
  		{
  			throw new NullPointerException();
  		}
  		synchronized (bcmListeners)
  		{
  			if (!bcmListeners.contains(listener))
  			{
  				bcmListeners.add(listener);
  			}
  		}
  	}