Vaadin app behind reverse proxy

I want to deploy a spring boot vaadin app behind an apache reverse proxy. The problem I have is theat the application runs on http://localhost:8080/ but should be accessible by http://myhost.com/myApp/.
It works if I want use the same path for both, e.g. http://myhost.com, but if the path is different Vaadin fails to load the bootstrap.js, because it igonres the path part introduced by the proxy.

Best wishes

Daniel