I'm playing with https://github.com/shred/acme4j, let's encrypt and undertow. I made some progress but it is hard to test if the certificate works without and real domain. I'm using ngrok but think there is a problem there with HTTPS... not sure.

Anyway, I want to know if there is a way to dynamically renew the certificate at runtime (no downtime).

Don't think is possible with existing API, is it?

Thanks