Symfony3 ClassNotFoundException après création d’un bundle

It is imperative to add its file in the composer.json

"autoload": {
        "psr-4": {
            "AppBundle\\": "src/AppBundle",
            "Acme\\Bundle\\BlogBundle\\": "src/Acme/Bundle/BlogBundle",
            "BlogBundle\\": "src/BlogBundle",
            "LangueBundle\\": "src/LangueBundle",
            "PaymentALBundle\\": "src/PaymentALBundle"

        },
        "classmap": [ "app/AppKernel.php", "app/AppCache.php" ]
    },

Then execute this command :

composer dumpautoload