Laravel error 'ReflectionException' - 'Class App\Http\Kernel does not exist' - php

Question

I was trying to go live with a laravel project i developped a year back in school and i ran into some issue.
After uploading the whole project on my hosting service's server, i got these errors on my browser as well as on my SSH shell.
Fatal error: Uncaught exception 'ReflectionException' with message 'Class App\Http\Kernel does not exist' in /home/clients/ffa41f94063541f86a0fe6602a73caa1/myforms/vendor/laravel/framework/src/Illuminate/Container/Container.php:779
Stack trace: #0 /home/clients/ffa41f94063541f86a0fe6602a73caa1/myforms/vendor/laravel/framework/src/Illuminate/Container/Container.php(779): ReflectionClass->__construct('App\Http\Kernel') #1 /home/clients/ffa41f94063541f86a0fe6602a73caa1/myforms/vendor/laravel/framework/src/Illuminate/Container/Container.php(659): Illuminate\Container\Container->build('App\Http\Kernel', Array) #2 /home/clients/ffa41f94063541f86a0fe6602a73caa1/myforms/vendor/laravel/framework/src/Illuminate/Foundation/Application.php(644): Illuminate\Container\Container->make('App\Http\Kernel', Array) #3 /home/clients/ffa41f94063541f86a0fe6602a73caa1/myforms/vendor/laravel/framework/src/Illuminate/Container/Container.php(229): Illuminate\Foundation\Application->make('App\Http\Kernel', Array) #4 /home/clients/ffa41f94063 in /home/clients/ffa41f94063541f86a0fe6602a73caa1/myforms/vendor/laravel/framework/src/Illuminate/Container/Container.php on line 779
I think it could be related to my namespace configuration, because i haven't all understood yet.
Here is my composer.json file :
{
"name": "laravel/laravel",
"description": "The Laravel Framework.",
"keywords": ["framework", "laravel"],
"license": "MIT",
"type": "project",
"require": {
"laravel/framework": "5.0.*",
"illuminate/html": "5.*",
"barryvdh/laravel-dompdf": "0.5.*",
"guzzlehttp/guzzle": "~4.0"
},
"require-dev": {
"phpunit/phpunit": "~4.0",
"phpspec/phpspec": "~2.1"
},
"autoload": {
"classmap": [
"database"
],
"psr-4": {
"App\\": "myforms/app/"
}
},
"autoload-dev": {
"classmap": [
"tests/TestCase.php"
]
},
"scripts": {
"post-install-cmd": [
"php artisan clear-compiled",
"php artisan optimize"
],
"post-update-cmd": [
"php artisan clear-compiled",
"php artisan optimize"
],
"post-create-project-cmd": [
"php -r \"copy('.env.example', '.env');\"",
"php artisan key:generate"
]
},
"config": {
"preferred-install": "dist"
}
}
What I have already done :
Delete /vendor and make a new install with composer install
composer dump-autoload
composer update
btw, I get the error when I insert the composer update
Please inform me if i should post another file that could be useful.
Thanks in advance for your help.

Answer 1

In composer.json change:
"psr-4": {
"App\\": "myforms/app/"
}
to:
"psr-4": {
"App\\": "app/"
}
On the server, in your source directory, run composer update then composer dump-autoload
PSR-4 in Laravel looks for namespaces relative to the root of the project

Answer 2

Check if console/kernel.php is inside of app-folder, if not it might be inside of your laravelApp.
If so, move console/kernel.php to app-folder.

Answer 3

In my case composer.json was missing propper bracket closing "{ }" and line with "psr-4" was in wrong json segment.
Check composer.json for proper align of "psr-4" it should be child of "autoload" section.
Remove vendor
composer install
OK

Answer 4

{
"name": "laravel/laravel",
"description": "The Laravel Framework.",
"keywords": ["framework", "laravel"],
"license": "MIT",
"type": "project",
"require": {
"laravel/framework": "5.0.*",
"illuminate/html": "5.*",
"barryvdh/laravel-dompdf": "0.5.*",
"guzzlehttp/guzzle": "~4.0"
},
"require-dev": {
"phpunit/phpunit": "~4.0",
"phpspec/phpspec": "~2.1"
},
"autoload": {
"classmap": [
"database"
],
"psr-4": {
"App\\": "myforms/app/"
}
},
"autoload-dev": {
"classmap": [
"tests/TestCase.php"
]
},
"scripts": {
"post-install-cmd": [
"php artisan clear-compiled",
"php artisan optimize"
],
"post-update-cmd": [
"php artisan clear-compiled",
"php artisan optimize"
],
"post-create-project-cmd": [
"php -r \"copy('.env.example', '.env');\"",
"php artisan key:generate"
]
},
"config": {
"preferred-install": "dist"
}
}

Answer 5

With the help of the other answers here, I realised I'd just missed a change when manually updating from Laravel 5.5 to 5.7
In composer.json, I'd missed this from the autoload block:
"autoload": {
"psr-4": {
"App\\": "app/"
},
...
},
If you're using version control, run composer update on your dev machine to update composer.lock. Then on your production server, you should only need to run composer install