juniorSpring
What is Inversion of Control (IoC) in Spring?
Updated May 17, 2026
Short answer
IoC is a design principle where Spring container manages object creation and lifecycle instead of the application code.
Deep explanation
In Spring, IoC shifts control of object creation from the developer to the framework. The Spring container reads configuration metadata and instantiates, configures, and manages beans. This improves decoupling and testability.
Real-world example
Instead of manually creating service objects in every controller, Spring injects them automatically.
Common mistakes
- Confusing IoC with DI
- IoC is the principle, DI is the implementation.
Follow-up questions
- How does Spring container manage bean lifecycle?
- What are benefits of IoC?