Questions
6 of 24
Explain the Dependency Inversion Principle (DIP). How does it relate to Dependency Injection?
Difficulty: 4/10
Dependency Inversion Principle
DIP states that high-level policy should not depend directly on low-level implementation details; both should depend on abstractions. It also states that abstractions should not depend on details—the details should depend on abstractions. Dependency Injection is a technique for supplying those dependencies from outside the consumer. Therefore, DIP is a design principle, while DI is one practical mechanism for implementing it.
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DIP is a design principle.
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Dependency Injection is a technique for supplying dependencies.
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High-level business logic should not construct infrastructure dependencies directly.
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Constructor injection makes dependencies explicit.
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DIP improves substitution, testing and architectural boundaries.
Follow-up Questions
- Is dependency injection required to implement DIP?
- What is constructor injection?
- What is the difference between DIP and DI?
- How does DIP improve testability?