The following article describes When should we use DI (Dependency Injection).

Dependency Injection (DI) is a design pattern that can be beneficial in many situations, particularly in complex enterprise applications where modular design, testability, and maintainability are critical. The following list shows some scenarios where using DI can be especially useful.

  1. Large applications with complex dependencies. In large enterprise applications, managing dependencies between objects can become complex and error-prone. So, DI can help simplify this process by delegating the responsibility of creating and managing dependencies to an external entity, such as a Spring container.
  2. Testability. Likewise, writing automated tests for applications can be difficult if the application’s components are tightly coupled. Therefore, by using DI, it’s possible to create mock objects or stubs to isolate and test individual components, making testing more straightforward and reliable.
  3. Flexibility and modular design. Similarly, applications that we design with DI are typically more modular, making it easier to swap out components or modify the application’s behavior without changing the entire codebase. As a result, we get more flexibility in our application for easy customization. So, it is now much easier to adapt to changing business requirements.
  4. Separation of concerns. Also, DI can help separate concerns by breaking up an application into loosely coupled components. Hence, it can improve maintainability by reducing the complexity of the code and making it easier to modify or refactor individual components without affecting the rest of the application.

In general, DI is useful in any situation where a clear separation of concerns and modular design are important. However, it’s important to keep in mind that introducing DI can also introduce additional complexity, especially in smaller or simpler applications. Accordingly, developers need to consider its advantages and drawbacks before using DI.

Further Reading

Spring Framework Practice Problems and Their Solutions

Java Practice Exercise