UIInitListener

A UIInitListener can be used to receive an event each time a new UI has been created and initialized.

The ideal place to add UIInitListeners would be inside a VaadinServiceInitListener

Java

public class ServiceListener implements VaadinServiceInitListener {
    @Override
    public void serviceInit(ServiceInitEvent event) {
        event.getSource().addUIInitListener(
                initEvent -> LoggerFactory.getLogger(getClass())
                        .info("A new UI has been initialized!"));
    }
}