Login in Java

try {
            Class.forName("com.mysql.jdbc.Driver");
            con =DriverManager.getConnection("jdbc:mysql://localhost/dbperpustakaan_10114287_10114299_10114336","root","");
            sql ="select * from tlogin where username='" + tnama.getText() + "'" + "AND password='" + tpas.getText() + "'" ;
            stat = con.createStatement();
            res = stat.executeQuery(sql);

            if(res.next()){
                JOptionPane.showMessageDialog(null, "Login Berhasil");
                menuutama mu = new menuutama();
                mu.setVisible(true);

                this.setVisible(false);
            } else {
                JOptionPane.showMessageDialog(null, "Usename atau Password anda Salah/Tidak Ditemukan silahkan Mendaftar");
            }
        } catch (Exception e) {
        }
    }