Rx is awesome, this add-on is awful. If you want compatible with Java 7 the

Directory RxVaadin
1

Rx is awesome, this add-on is awful. If you want compatible with Java 7 then don’t use lambda. If you want only support Java 8 then use lambda. Don’t mix them up.

2

I’m afraid that you are right, this add-on requires Java 8. This is explicitly stated in the Github project description.