Class Firebase\JWT\JWT not found

Question

I want to use pure firebase/php-jwt library in my code. Firstly, I go to /var/www/html/ and like the official library page is suggesting, I do this

Answer 1

If not using composer for maintaining the structure. just remove

namespace Firebase\JWT;
use \DomainException;
use \InvalidArgumentException;
use \UnexpectedValueException;
use \DateTime;

* 
* JSON Web Token implementation, based on this spec:
* https://tools.ietf.org/html/rfc7519
 *
* PHP version 5
*
* @category Authentication
* @package  Authentication_JWT
* @author   Neuman Vong 
* @author   Anant Narayanan 
* @license  http://opensource.org/licenses/BSD-3-Clause 3-clause BSD
* @link     https://github.com/firebase/php-jwt

form your JWT.php file. It works fine for me know.