LLDbeginner
Dependency Injection
Dependency Injection makes systems easier to test, configure, and extend by supplying dependencies from outside rather than hardcoding them inside classes.
Reading time
8 min
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The Core Idea
A class should not construct every dependency it uses. Instead, those dependencies should be provided to it through a constructor or configuration mechanism.
Benefits
- Easier unit testing
- Lower coupling
- Better configurability
- More alignment with dependency inversion
Common Forms
- Constructor injection
- Setter injection
- Framework-managed injection
Interview Tip
If your classes depend on interfaces rather than concrete implementations, DI is usually part of the story.