@Temporal tells JPA how to map generic date/time types like java.util.Date and I believe also java.util.Calendar to date, time or datetime columns. Other types like java.sql.Date, java.sql.Time, java.sql.Timestamp and classes from java.time already contain information to auto-guess the database type, but java.util.Date is so generic that it can be mapped to any of the three.
Stefan, you said you changed the value in @Temporal. Did you also change the actual database column type? Because the two must match. And if you want the date and time, you should use TIMESTAMP, not TIME. DATE is only the date part, TIME is only the time part, TIMESTAMP is both combined.