Suppose I'm making a JDBC call and I had fetched data from a database to a
Even if you could, you shouldn't unless you are coding against a very specific jdbc driver. In some cases, the result set will not be constructed at all. In others (Oracle IIRC), you could configure it so that it only fetches a give number of rows out of the total.
However, in general, if you lose the connection, you have more things to worry about than wondering if you can iterate over a partially fetched resulst set object. In such cases, the rule of thumb is
Also, as a rule of thumb, you should not worry about partial failures when executing statements within a transaction. Discard and retry fresh.
In some rare cases the DB can send you a vendor specific code (SQLException.getErrorCode()) that can tell you whether the operation can be retried. Oracle has some specific codes (don't remember them) for cases when you do an insert and a unique constrain has been violated. Sometimes such failed operations can be retried, but that's vendor and business specific.
In general, just dump the mauled result set and start over.