Comment by typicalrunt

The site is down for me right now so I'll plead ignorance about #4.

How does one goes about implementing #4? I can abstract away a REST API call for Avatars, but how does one do that for a database? Or is this just a fancy way of saying (in Java-speak), use Interfaces.

[Edit: the site is back up and I was able to read it. The premise reads differently than how the parent wrote it. I read it mainly as, the sysadmin should be able to switch to a new host, change the configuration file, bounce the application, and everything should work.]