code: protected AjaxRadio<T> newAjaxRadio(final String id, final RadioGroup<T> group,
  		final ListItem<T> item)
  	{
  		return new AjaxRadio<T>("radio", item.getModel())
  		{
  			private static final long serialVersionUID = 1L;
  
  			@Override
  			public void onClick(final AjaxRequestTarget target)
  			{
  				onRadioSelect(target, group.getModelObject());
  			}
  		};
  	}
docs: Factory method for create the new {@link AjaxRadio}. This method is invoked in the
  constructor from the derived classes and can be overridden so users can provide their own
  version of a new {@link AjaxRadio}.
  
  @param id
  the id
  @param group
  the group
  @param item
  the item
  @return the new {@link AjaxRadio}.