# Dependency Injection & Services (Symfony)

> Service container, autowiring, service configuration, tags, decoration, aliases

- 24 interview questions
- Mid-Level
- [Interview Questions: Symfony](https://sharpskill.dev/en/technologies/symfony/interview-questions.md)

## 1. What is the main role of the service container in Symfony?

**Answer**

The service container (or Dependency Injection Container) is responsible for creating, configuring, and managing the lifecycle of all application services. It enables automatic dependency injection into classes, promoting loose coupling and facilitating unit testing.

## 2. What is autowiring in Symfony?

**Answer**

Autowiring is a feature that allows the container to automatically resolve service dependencies by analyzing the type-hints of constructor parameters. This avoids having to manually configure each dependency injection in YAML or PHP files.

## 3. What is the difference between a public and a private service in Symfony?

**Answer**

A public service can be retrieved directly from the container via get(), while a private service can only be injected as a dependency of other services. Since Symfony 4, services are private by default to improve performance and encourage dependency injection over direct container access.

## 21 more questions available

- How to inject a service into a Symfony controller using autowiring?
- What does the autoconfigure option do in Symfony service configuration?

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## Other Symfony interview topics

- [Modern PHP (8.1+)](https://sharpskill.dev/en/technologies/symfony/interview-questions/php-modern-features.md): 20 questions, Junior
- [Symfony Basics](https://sharpskill.dev/en/technologies/symfony/interview-questions/symfony-basics.md): 25 questions, Junior
- [Routing & Controllers](https://sharpskill.dev/en/technologies/symfony/interview-questions/routing-controllers.md): 20 questions, Junior
- [Twig & Templates](https://sharpskill.dev/en/technologies/symfony/interview-questions/twig-templates.md): 20 questions, Junior
- [Doctrine ORM Basics](https://sharpskill.dev/en/technologies/symfony/interview-questions/doctrine-orm-basics.md): 25 questions, Junior
- [Symfony Forms](https://sharpskill.dev/en/technologies/symfony/interview-questions/forms.md): 22 questions, Junior
- [Data Validation](https://sharpskill.dev/en/technologies/symfony/interview-questions/validation.md): 18 questions, Junior
- [Security & Authentication](https://sharpskill.dev/en/technologies/symfony/interview-questions/security-authentication.md): 26 questions, Mid-Level
- [Doctrine Advanced](https://sharpskill.dev/en/technologies/symfony/interview-questions/doctrine-advanced.md): 24 questions, Mid-Level
- [API Platform](https://sharpskill.dev/en/technologies/symfony/interview-questions/api-platform.md): 22 questions, Mid-Level
- [Serializer Component](https://sharpskill.dev/en/technologies/symfony/interview-questions/serializer.md): 20 questions, Mid-Level
- [Events & Event Subscribers](https://sharpskill.dev/en/technologies/symfony/interview-questions/events-subscribers.md): 20 questions, Mid-Level
- [Console & Commands](https://sharpskill.dev/en/technologies/symfony/interview-questions/console-commands.md): 18 questions, Mid-Level
- [Messenger Component](https://sharpskill.dev/en/technologies/symfony/interview-questions/messenger.md): 22 questions, Mid-Level
- [HTTP Client](https://sharpskill.dev/en/technologies/symfony/interview-questions/http-client.md): 18 questions, Mid-Level
- [Cache & Performance](https://sharpskill.dev/en/technologies/symfony/interview-questions/cache.md): 20 questions, Mid-Level
- [Workflow Component](https://sharpskill.dev/en/technologies/symfony/interview-questions/workflow.md): 18 questions, Mid-Level
- [Testing Symfony](https://sharpskill.dev/en/technologies/symfony/interview-questions/testing.md): 22 questions, Mid-Level
- [Mailer Component](https://sharpskill.dev/en/technologies/symfony/interview-questions/mailer.md): 16 questions, Mid-Level
- [Translations & i18n](https://sharpskill.dev/en/technologies/symfony/interview-questions/translations.md): 16 questions, Mid-Level
- [EasyAdmin Bundle](https://sharpskill.dev/en/technologies/symfony/interview-questions/easyadmin.md): 18 questions, Mid-Level
- [Symfony Architecture](https://sharpskill.dev/en/technologies/symfony/interview-questions/architecture-patterns.md): 24 questions, Senior
- [Performance & Optimization](https://sharpskill.dev/en/technologies/symfony/interview-questions/performance-optimization.md): 22 questions, Senior
- [Security Advanced](https://sharpskill.dev/en/technologies/symfony/interview-questions/security-advanced.md): 22 questions, Senior
- [Custom Bundles](https://sharpskill.dev/en/technologies/symfony/interview-questions/custom-bundles.md): 20 questions, Senior
- [Microservices with Symfony](https://sharpskill.dev/en/technologies/symfony/interview-questions/microservices.md): 22 questions, Senior
- [Real-time & WebSockets](https://sharpskill.dev/en/technologies/symfony/interview-questions/real-time.md): 18 questions, Senior
- [Deployment & DevOps](https://sharpskill.dev/en/technologies/symfony/interview-questions/deployment-devops.md): 20 questions, Senior

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