Are there guidelines established for persisting threeten classes to databases? For the purposes of this question we can separate date and time classes in three categories:

I'm supposing a database with support for storing the usual primitives and timestamps. The latter are represented as java.util.Dates in the API.

For Instants seems a no brainer to map from and to j.u.Date s.

So far I haven't needed to map Unanchored classes, so I haven't put much thought.

For Anchored classes, I can see several approaches:


Now with the questions :)

Has anyone else explored this space? Am I missing something in this characterization? What option are you guys usually leaning towards? 

Thanks and sorry for the explosion of bullet points.

--
Rafael de F. Ferreira.
http://www.rafaelferreira.net/