How can class definitions be properly handled when storing objects in PHP sessions?

When storing objects in PHP sessions, class definitions need to be included before accessing the stored objects to prevent errors. This can be achieved by either including the class definition in every script that accesses the session data or using autoloading to automatically load the class definition when needed.

// Include class definition before accessing session data
require_once 'path/to/ClassDefinition.php';

// Start the session
session_start();

// Store object in session
$_SESSION['object'] = new ClassName();

// Access object from session
$object = $_SESSION['object'];