Dependency injection is a design pattern that separates the responsibility of creating an object from the responsibility of using it, by passing (injecting) a required object into a class rather than letting that class construct it internally; this is a form of inversion of control and improves testability. Dependency inversion is a distinct design principle, part of the SOLID principles, that decouples concrete classes by introducing an abstraction (an abstract class or interface) between them, which is only achievable once creation and use have already been separated via dependency injection. Both concepts belong to object-oriented software design, specifically the study of class coupling — the direct relationships (attribute typing, parameter passing, inheritance) that bind classes together, with inheritance being the strongest and most rigid form of coupling.
Dependency injection is a design pattern that separates the responsibility of creating an object from the responsibility of using it, by passing (injecting) a required object into a class rather than…