It is funny how exotic computer technology eventually either fails or becomes commonplace. At one time, having more than one user on a computer at once was high tech, for example. Then there are ...
If resource permits, definitely use the DB. A plain text file is hard to "use" (unless writing a shit load of perl or whatever just to digest the file is within your definition of easy); a DB, OTOH, ...
JPA-based applications can't connect to a database on their own. Rather, they need help in terms of what credentials to use, which schema to seek, which JDBC driver to select and which annotated ...