What are the benefits and drawbacks of using SingletonPattern versus Dependency Injection Container for managing class instances in PHP?

Issue: When managing class instances in PHP, developers often debate between using the Singleton Pattern or a Dependency Injection Container. The Singleton Pattern ensures that only one instance of a class exists throughout the application, while a Dependency Injection Container allows for easier management and injection of dependencies. Singleton Pattern: Benefits: 1. Ensures only one instance of a class exists throughout the application. 2. Provides a global point of access to the instance. 3. Easy to implement and understand. Drawbacks: 1. Can lead to tightly coupled code. 2. Difficult to unit test. 3. Can hinder scalability and maintainability. Dependency Injection Container: Benefits: 1. Promotes loose coupling between classes. 2. Allows for easier management and injection of dependencies. 3. Improves testability and maintainability. Drawbacks: 1. Requires additional setup and configuration. 2. Can introduce complexity to the codebase. 3. May not be suitable for small projects. PHP code snippet implementing Singleton Pattern:

class Singleton {
    private static $instance;

    private function __construct() {
        // Private constructor to prevent instantiation
    }

    public static function getInstance() {
        if (self::$instance === null) {
            self::$instance = new self();
        }
        return self::$instance;
    }
}

$singletonInstance = Singleton::getInstance();
```

PHP code snippet implementing Dependency Injection Container:

```php
class Dependency {
    // Class with dependencies
}

class DependencyInjectionContainer {
    private $dependencies = [];

    public function __construct() {
        $this->dependencies['dependency'] = new Dependency();
    }

    public function getDependency($name) {
        return $this->dependencies[$name];
    }
}

$container = new DependencyInjectionContainer();
$dependency = $container->getDependency('dependency');