Question: What Is Difference Between @Inject And @Autowired?

Is Autowired mandatory?

1 Answer.

Is @Autowired annotation mandatory for a constructor.

No.

After Spring 4.3 If your class has only single constructor then there is no need to put @Autowired ..

Which dependency injection is not possible in spring?

With setter injection, Spring allows us to specify optional dependencies by adding @Autowired(required = false) to a setter method. This is not possible with constructor injection since the required=false would be applied to all constructor arguments.

Why dependency injection is used in spring?

Dependency Injection is a fundamental aspect of the Spring framework, through which the Spring container “injects” objects into other objects or “dependencies”. Simply put, this allows for loose coupling of components and moves the responsibility of managing components onto the container.

Which Dependency Injection is best in spring?

On the other hand, constructor injection uses the constructor to inject dependency on any Spring-managed bean. 2) Because of using the setter method, setter Injection in more readable than constructor injection in Spring configuration file usually applicationContext.

Can we use @bean at class level?

@Component is a class level annotation whereas @Bean is a method level annotation and name of the method serves as the bean name. @Component need not to be used with the @Configuration annotation where as @Bean annotation has to be used within the class which is annotated with @Configuration.

Which Dependency Injection is best?

Getters and setters are generally considered best practices in object-oriented programming. It’s trivial to instruct Spring to use the setter for dependency injection by annotating the setter method.

What will happen if we interchange @service and @repository annotation in the Spring MVC?

First reason: any of this annotations make clear the role of your component in the application. … For example, Spring Data JPA will process @Repository , and will try to replace with implementation any interface marked by this annotaion. Spring also will apply automatic exception translation to such classes.

Should I use Autowired or inject?

Better use @Inject all the time. Because it is java configuration approach(provided by sun) which makes our application agnostic to the framework. So if you spring also your classes will work. If you use @Autowired it will works only with spring because @Autowired is spring provided annotation.

What does @controller do in spring?

Typically, in Spring MVC, we write a controller class to handle requests coming from the client. Then, the controller invokes a business class to process business-related tasks, and then redirects the client to a logical view name, which is resolved by Spring’s dispatcher servlet in order to render results or output.

What is spring bean life cycle?

A “Spring bean” is just a Spring managed instantiation of a Java class. The Spring IoC container is responsible for instantiating, initializing, and wiring beans. The container also manages the life cycle of beans. Spring provides several ways through which you can tap into the bean lifecycle.

What’s the difference between @component @repository & @service annotations in spring?

The difference between them is, @component is used to annotate compound classes, @Repository is a marker for automatic exception translation in the persistence layer, for service layer we need to use @service. You can refer Spring Documentation to know more.

What is the difference between @autowired and @bean?

Annotating @Bean only registers the service as a bean(kind of an Object) in spring application context. In simple words, it is just registration and nothing else. @Autowired BookingService bookingService; Annotating a variable with @Autowired injects a BookingService bean(i.e Object) from Spring Application Context.

What does Autowired mean in spring?

Autowiring feature of spring framework enables you to inject the object dependency implicitly. It internally uses setter or constructor injection. Autowiring can’t be used to inject primitive and string values. It works with reference only.

What is the difference between controller and RestController in spring?

1. The @Controller is a common annotation that is used to mark a class as Spring MVC Controller while @RestController is a special controller used in RESTFul web services and the equivalent of @Controller + @ResponseBody.

What is the difference between @inject and @autowired?

The @Autowired annotation is used for auto-wiring in Spring framework. … The @Inject annotation also serves the same purpose, but the main difference between them is that @Inject is a standard annotation for dependency injection and @Autowired is spring specific.

The reasons why field injection is frowned upon are as follows: You cannot create immutable objects, as you can with constructor injection. Your classes have tight coupling with your DI container and cannot be used outside of it. Your classes cannot be instantiated (for example in unit tests) without reflection.

Is Autowired a dependency injection?

Dependency injection is injecting one or more beans to a single bean via constructor or setter method. Spring also provides autowired dependency injection. We only need to annotate our field, setter method or constructor by @Autowire annotation. Dependency injection can be resolved using XML or JavaConfig.

What is a bean in spring?

In Spring, the objects that form the backbone of your application and that are managed by the Spring IoC container are called beans. A bean is an object that is instantiated, assembled, and otherwise managed by a Spring IoC container. Otherwise, a bean is simply one of many objects in your application.