Dependency injection frameworks

Application frameworks such as SpringGuicePlay frameworkSaltaGlassfish HK2, and Microsoft Managed Extensibility Framework (MEF) support dependency injection but are not required to do dependency injection.


  • Dependency injection allows a client the flexibility of being configurable. Only the client's behavior is fixed. The client may act on anything that supports the intrinsic interface the client expects.
  • Dependency injection can be used to externalize a system's configuration details into configuration files allowing the system to be reconfigured without recompilation. Separate configurations can be written for different situations that require different implementations of components. This includes, but is not limited to, testing.
  • Because dependency injection doesn't require any change in code behavior it can be applied to legacy code as a refactoring. The result is clients that are more independent and that are easier to unit testin isolation using stubs or mock objects that simulate other objects not under test. This ease of testing is often the first benefit noticed when using dependency injection.
  • Dependency injection allows a client to remove all knowledge of a concrete implementation that it needs to use. This helps isolate the client from the impact of design changes and defects. It promotes reusability, testability and maintainability.
  • Reduction of boilerplate codein the application objects since all work to initialize or set up dependencies is handled by a provider component.
  • Dependency injection allows concurrent or independent development. Two developers can independently develop classesthat use each other, while only needing to know the interface the classes will communicate through. Plugins are often developed by third party shops that never even talk to the developers who created the product that uses the plugins.
  • Dependency Injection decreases coupling between a class and its dependency.


  • Dependency injection creates clients that demand configuration details be supplied by construction code. This can be onerous when obvious defaults are available.
  • Dependency injection can make code difficult to trace (read) because it separates behavior from construction. This means developers must refer to more files to follow how a system performs.
  • Dependency injection typically requires more upfront development effort since one can not summon into being something right when and where it is needed but must ask that it be injected and then ensure that it is injected.
  • Dependency injection can cause an explosion of types, especially in languages that have explicit interface types, like Java and C# 
  • Dependency injection forces complexity to move out of classes and into the linkages between classes which might not always be desirable or easily managed.
  • Ironically, dependency injection can encourage dependence on a dependency injection framework.