Laravel 5 Unable to detect application namespace

Okay, I solved it. What I did to solve this:

composer update

gave me following error:

[Seld\JsonLint\ParsingException]

"./composer.json" does not contain valid JSON
 Parse error on line 9:
"require-dev
 ---------------------^
 Expected: 'STRING' - It appears you have an extra trailing comma

I opened composer.json and there was one extra comma in last line:

"require": {
    "php": ">=5.5.9",
    "laravel/framework": "5.1.*",
}

Removed the comma so it looked like this:

"require": {
    "php": ">=5.5.9",
    "laravel/framework": "5.1.*"
}

And problem was gone.