Class.forName("com.mysql.jdbc.Driver");

        connection = DriverManager.getConnection(URL,USER_NAME,PASSWORD);

         String checkingUser = "SELECT nick_name FROM users WHERE nick_name=? AND password=? AND users.email=?";

        PreparedStatement preparedStatement = connection.prepareStatement(checkingUser);
        System.out.println("Before 1");
        preparedStatement.setString(1,loginData[0]);
        System.out.println("Before 2");
        preparedStatement.setString(2,loginData[1]);
        System.out.println("Before 3");
        preparedStatement.setString(3,loginData[2]);
        preparedStatement.execute();

  com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException:
  You have an   error in your SQL syntax; check the manual that
  corresponds to your MySQL server version for the right syntax to user near '?, password=?, users.email=?' at line 1