public boolean Authentification(String login,String pwd){
        String requete = "select * from user where Login=? and Password=?";
        try 
        {
            PreparedStatement ps = MyConnection.getInstance().prepareStatement(requete);
            ps.setString(1,login);
            ps.setString(2,pwd);
            ResultSet resultat = ps.executeQuery();
            if (resultat.next())
            {
               System.out.println("returned true");
               return true;
            } else {
                System.out.println("returned false");
                return false;
            }
        }catch(SQLException ex) {
            System.out.println("Exception : "+ex.getMessage());        
        }
        return false;
    }