isc_tr_handle tr = lookupXid(xid);
isc_tr_handle tr = getTrHandleForXid(xid);
    void rollback(Xid xid) throws XAException {        isc_tr_handle tr = lookupXid(xid);        forgetResultSets(tr);        try {            gds.isc_rollback_transaction(tr);        }        catch (GDSException ge) {            throw new XAException(ge.getMessage());        }        finally {            forgetXid(xid);        }    }