private void disconnect()
        {
            try { jc.CloseConnection(); }
            catch (Exception) { }

            try { mc.CloseConnection(); }
            catch (Exception) { }

            try { lc.CloseConnection(); }
            catch (Exception) { }

            try { msc.CloseConnection(); }
            catch (Exception) { }

            jc = null; mc = null; lc = null; msc = null;
        }