The section about retrieving the bound port for an embedded web server had only the proper interface for servlet-based servers, not for reactive servers. It took me a while to figure it out, so adding what I found here might save other people the time that it cost me.

Comment From: snicoll

@johncfranco thank you for making your first contribution to Spring Boot. It turns out that How-To was a little bit outdated anyway as we have a common abstraction between Servlet-based and Reactive web apps. I've polished your contribution to mention how you can listen to a common event that works in both arrangements.