Looking for example code and/or tutorial of Java Vaadin Front-end accessing

Am on a new project where they want to use Vaadin on the front-end so it can be supported by Java developers but utilizes a REST API architecture for backend integration, so if UI gets more complex over time the app can be migrated to a Javascript framework like React.

So looking for some sample code and/or tutorial which shows how this can be done, which is beyond just Spring for backend integration which is what most of the examples use it seems. Thx

This is a pretty old example, but the ideas should all still work: https://vaadin.com/tutorials/consuming-rest-services-from-java-applications