What is Dependency Injection in Spring?
Dependency Injection (DI) is a design pattern used in software development, and it plays a significant role in the Spring Framework, which is a popular framework for building Java-based enterprise applications. Dependency Injection is a technique where one object supplies the dependencies of another object, rather than the dependent object creating them itself. In other words, it’s a way to achieve Inversion of Control (IoC), where the control over the flow of a program’s execution is shifted from the program itself to a framework or container.
In the context of Spring, Dependency Injection is used to manage the dependencies between various components of an application, such as classes, beans, or services. Spring provides a container (often called the “Spring IoC container”) responsible for instantiating, configuring, and managing these objects. The container injects the required dependencies into objects at runtime, allowing you to build loosely coupled and highly maintainable applications.
Spring – When to Use @Qualifier and @Autowired For Dependency Injection
In the world of Spring Framework, managing dependencies is a fundamental aspect of building robust and maintainable applications. Spring offers two primary annotations to facilitate dependency injection: @Autowired and @Qualifier. Understanding when and how to use these annotations is crucial for effective bean wiring .@Autowired and @Qualifier are both annotations used in Spring Framework to work with dependency injection, but they serve different purposes.