Well at least we have:
The source code of the tutorial in tne github
https://github.com/vaadin/cdi-tutorial/tree/master/src/main/java/com/vaadin/cdi/tutorial
The DOC- Vaadin CDI Add on
https://vaadin.com/docs/v8/framework/advanced/advanced-cdi.html
The “false” - vaadin CDI tutorial
https://vaadin.com/docs/v8/framework/articles/VaadinCDI.html