Vaadin 8 | Notifications - appreciated/vaadin-app-layout GitHub Wiki
To show to the user notifications. You can do as follows:
public class DemoUI extends UI {
DefaultNotificationHolder notifications = new DefaultNotificationHolder();
@Override
protected void init(VaadinRequest request) {
AppLayout drawer = AppLayoutBuilder.get(variant)
...
.addToAppBar(new AppBarNotificationButton(notifications, true);
...
.build();
setContent(drawer);
}
}