The Sun JDK doesn't exhibit a 'JDBC Version'. The classes provided in the Sun API are merely interfaces. It's the JDBC Drivers, obtained separately and specific to each kind of database, which exhibit 'versionness', and as far as I'm aware the way to decide if any given JDBC driver will do what you want is to use the class I've already pointed out.
If the JDBC driver jar provides an implementation of javax.sql.DataSource then it supports both the old (via DriverManager) and new way (DataSource implementation registered via a JNDI provider) of creating connections.
Tim