<?php

define("START", microtime(true));
define("ROOT", realpath(__DIR__.'/../'));

include '../vendor/autoload.php';

include ROOT . '/application/Library/Application.php';

AppApplication::getClass('test')->test();

"autoload": {
    "psr-4": {
        "App\": "application/"
    }
}

include ROOT . '/application/Library/Application.php';

<?php

namespace App;

class Application
{
    public static function getClass($library){} // removed body for minimal example
}

?>