Symfony 2 and ZipArchive - class not found!

It was crazy. I was trying to make my ZipArchive work and I know now, that it was already working just Symfony2 did not knew about it!

Fatal error: Class 'Demo\AcmeBundle\Controller\ZipArchive' not found 

How to use template engine in Symfony 2?

Symfony 2 comes bundled with Twig template engine, so you definitely want to use it. Twig template engine has everything what you need to keep your business logic out of templates and stay on MVC pattern, which is used in Symfony 2. The best thing about Twig template engine is that in many cases it is even faster than raw PHP, because finally it renders to raw and optimised PHP code.