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What is dependency injection in Java?
Updated May 6, 2026
Short answer
Dependency Injection is a design pattern where dependencies are provided externally instead of created inside a class.
Deep explanation
It promotes loose coupling by delegating object creation to frameworks or external configuration. Common in Spring Framework.
Real-world example
Used in Spring Boot applications for service and repository wiring.
Common mistakes
- Creating dependencies using 'new' inside classes.
Follow-up questions
- What are types of DI?
- Why is DI useful?