$("#logger-button").click(function () {

var loginData = {

nickName:$("#user-name").val(),
email:$("#email").val(),
password:$("#password").val(),
formId:$("#loginForm").val()
}

var JSONString = JSON.stringify(loginData);

console.log(JSONString);

var url = "http://localhost:8080/CouponProject/login";

$.ajax({

    url:url,
    method:"post",
    data:JSONString,
    contentType:"application/json",
    error:function (message) {
        console.log(message);
    },
    success:function (data) {

        console.log(data); // line 29

        var JSONObject = JSON.parse(data); // line 31
        console.log(JSONObject);

    },
    headers:
    {
        "Accept":"application/json",
        "Accept-Language":"en",
        "Cache-Control":"max-age=3600"
    }
});

protected static boolean postDatabase(String[] loginData, HttpServletResponse response) throws IOException {
  try {
    output = response.getWriter();
    Class.forName("com.mysql.jdbc.Driver");
    connection = DriverManager.getConnection(URL, USER_NAME, PASSWORD);
    String checkingUser = "SELECT nick_name,email,password FROM users WHERE nick_name=?";
    PreparedStatement preparedStatement = connection.prepareStatement(checkingUser);
    preparedStatement.setObject(1, loginData[0]);
    ResultSet resultSet = preparedStatement.executeQuery();
    while (resultSet.next()) {
      int passwordColumn = resultSet.findColumn("password");
      int emailColumn = resultSet.findColumn("email");

            System.out.println(passwordColumn);
            System.out.println(emailColumn);

            System.out.println(resultSet.getString(passwordColumn)); // correct
            System.out.println(resultSet.getString(emailColumn));// correct

      if (resultSet.getString(passwordColumn).equals(loginData[1])) {
        System.out.println(resultSet.getString(passwordColumn));
        if (resultSet.getString(emailColumn).equals(loginData[2])) {
          ResponseDataHandler.ToJSONresponse("success", response);
        }
      }
    }
  } catch (IOException ioError) {
    ResponseDataHandler.ToJSONresponse(ioError.toString(), response);
  } catch (ClassNotFoundException notFound) {
    ResponseDataHandler.ToJSONresponse(notFound.toString(), response);
  } catch (SQLException sql) {
    ResponseDataHandler.ToJSONresponse(sql.toString(), response);
  } finally {
    try {
      connection.close();
    } catch (SQLException sql) {
      ResponseDataHandler.ToJSONresponse(sql.toString(), response);
    }
  }
  return false;
}