Prosedur Menampilkan Isi Data Base Ke JComboBox (NetBeans)

private  void tampil_tanggal(){
    try {
            sambung_db();
            String sql="SELECT tgl_produksi FROM produksi";
            Statement stat=conn.createStatement();
            ResultSet res=stat.executeQuery(sql);
            while (res.next()){
                jComboBox_dari_tgl.addItem(res.getString(1));
                jComboBox_ke_tgl.addItem(res.getString(1));
            }       
    } catch (Exception e) {
    }
}