private void loginBTNActionPerformed(java.awt.event.ActionEvent evt) {

        String s1 = userTF.getText();
        String s2 = passTF.getText();
        boolean isEmpty = false;
        boolean isUserExist = false;

        if(s1.equals("") || s2.equals("")){
            isEmpty = true;
            JOptionPane.showMessageDialog(null, "All fields are mandatory");

        }

        if(!isEmpty){
        try{
            Class.forName("java.sql.Driver");
            Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/db", "root", "lego");
            Statement st = con.createStatement();

            String studentlogin = "Select * from student where user ='"+s1+"';";
            ResultSet rs = st.executeQuery(studentlogin);



            while(rs.next()){
                isUserExist = true;
                String user=rs.getString("user");
                String pass=rs.getString("pass");

                if(s1.equals(user) && s2.equals(pass)){
                    System.out.println("Login Successful");
                    studentHomePage s = new studentHomePage(user);
                    st.close();
                    con.close();
                    s.setVisible(true);
                    this.dispose();

                    break;
                } else {

                   JOptionPane.showMessageDialog(null, "Password incorrect");

                }

            }

            if(!isUserExist){
                JOptionPane.showMessageDialog(null, "Username does not exist");
            }


        } catch(Exception e){
            System.out.println(e);
        }

        }
    }