Distinction between @Autowired and @Inject annotation in Spring?

What’s the distinction between @Autowired and @Inject annotation in Spring is likely one of the often requested Spring questions on Java interviews? Since all people is now moved or shifting to annotation-driven and Java configuration in Spring, this query has change into much more essential for potential candidates searching for a Java net improvement job utilizing the Spring framework. The @Autowired annotation is used for auto-wiring within the Spring framework. If you do not know, autowiring is a course of on which the Spring framework determine the dependencies of a Spring bean, as an alternative of you, a developer, explicitly specifying them within the software context file. You possibly can annotate fields and constructor utilizing @Autowired to inform Spring framework to seek out dependencies for you.

The @Inject annotation additionally serves the identical function, however the principle distinction between them is that @Inject is a customary annotation for dependency injection and @Autowired is spring particular.

Since Spring isn’t the one framework that gives dependency injection, sooner or later for those who change your container and strikes to a different DI framework like Google Guice, you might want to reconfigure your software.

You possibly can doubtlessly keep away from that improvement effort through the use of customary annotations specified by JSR-330 e.g.  @Inject, @Named, @Qualifier, @Scope, and @Singleton.

A bean declared to be auto-wired utilizing @Inject will work in each Google Guice and Spring framework, and doubtlessly some other DI container which helps JSR-330 annotations.

Good data of important Spring annotations is essential for a hands-on developer.

Distinction between @Autowired vs @Inject Annotation?

When you have labored with Hibernate and JPA in previous then JSR-330 annotation is nothing however like JPA annotations which standardize the Object-Relational mapping throughout the framework. Once you use the JPA annotations like @Entity, your code is not going to solely work on Hibernate but in addition on different ORM instruments and frameworks like Eclipse TopLink.

Btw, like all comparable issues on this planet, regardless that each @Autowired and @Inject serve the identical function there are a few variations between them, let’s study them briefly

1. The primary and most essential distinction between @Autowired and @Inject annotation is that the @Inject annotation is barely out there from Spring 3.0 onwards, so if you wish to use annotation-driven dependency injection in Spring 2.5 then you must use the @Autowired annotation.

2. The second distinction between these two annotations is that, not like Spring’s @Autowired,  the @Inject doesn’t require the ‘required’ attribute.

3. The third most typical distinction between @Autowired and @Inject annotation is that the previous is Spring particular whereas the latter is the usual for Dependency Injection, laid out in JSR-330.

Generally, I like to recommend using JSR 330 annotation for DI, the @Inject annotation is as succesful as Spring’s @Autowired, and if you’d like you may as well combine and match this with Spring’s @Worth and @Lazy annotations.

4. The @Autowired annotation was added on Spring 2.5 and used for annotation-driven dependency injection. It really works at the side of @Part annotation and <context:component-scan /> to streamline improvement cycle.

From Spring 3.0, Spring provides assist for JSR-330 dependency injection annotations like @Inject, @Named, and @Singleton. It additionally added extra Spring particular annotations like @Main, @Lazy, and @DependsOn annotation.

5. The @Inject annotation is sweet from the portability standpoint. Since @Autowired is particular to the Spring framework, for those who ever determined to maneuver to Google Guice or some other dependency injection framework then you might want to re-implement your dependency injection logic, regardless that your software stays the identical. All bean creation logic must be modified to match with Google Guice’s implementation.

Right here is an additionally good abstract of Spring annotations vs JSR 330 annotation to check them aspect by aspect, that is helpful to seek out an equal customary annotation for a spring-specific annotation e.g. you need to use @Named rather than @Qualifier, and so forth.