MaterialDropDown.java

public class MaterialDropDown extends UnorderedList implements HasSelectionHandlers<Widget>, HasInOutDurationTransition, Loader, HasConfigure {

    ...
    JsDropdownOptions options = new JsDropdownOptions();

    @Override
    protected void onLoad() {
        super.onLoad();

        Widget parent = getParent();
        if (parent instanceof HasActivates) {
            String uid = DOM.createUniqueId();
            ((HasActivates) parent).setActivates(uid);
            setId(uid);
            activatorElement = parent.getElement();
        } else if (activatorElement == null) {
            activatorElement = DOMHelper.getElementByAttribute("data-activates", activator);
            if (activatorElement == null) {
                GWT.log("There is no activator element with id: '" + activator + "' in the DOM, " +
                        "cannot instantiate MaterialDropDown without a data-activates.", new IllegalStateException());
            }
        }

        configure();
        load();
    }

    @Override
    public void configure() {
        options.constrain_width = constrainWidth;
        options.inDuration = inDuration;
        options.outDuration = outDuration;
        options.hover = hover;
        options.gutter = gutter;
        options.belowOrigin = belowOrigin;
        options.alignment = alignment.getCssName();
    }
  
    @Override
    public void load() {
        $(activatorElement).dropdown(options);
        setupActivator(); 
    }

    @Override
    public void reload() {
        remove(activatorElement);
        configure();
        load();
    }
    
  ...
}