code: @Override
  	protected final void onRender()
  	{
  		Iterator<? extends Component> it = renderIterator();
  		while (it.hasNext())
  		{
  			Component child = it.next();
  			if (child == null)
  			{
  				throw new IllegalStateException(
  					"The render iterator returned null for a child. Container: " + this.toString() +
  						"; Iterator=" + it.toString());
  			}
  			renderChild(child);
  		}
  	}
docs: Renders all child items in no specified order