introduction.rst

The Class Loader Component

The Class Loader Component loads your project classes automatically.

Whenever you use an undefined class, PHP uses the autoloading mechanism to delegate the loading of a file defining the class. Symfony2 provides two autoloaders, which are able to load your classes:

• :doc:`A PSR-0 class loader<class_loader>`
• :doc:`Load classes based on class-to-file mapping<map_class_loader>`

Additionally, the Symfony Class Loader Component ships with a set of wrapper classes which can be used to add additional functionality on top of existing autoloaders:

• :doc:`cache_class_loader`
• :doc:`debug_class_loader`

Installation

You can install the component in 2 different ways:

• Use the official Git repository (https://github.com/symfony/ClassLoader);
• :doc:`Install it via Composer </components/using_components>` (symfony/class-loader on Packagist).