What Is @Service Annotation In Spring?

What is @controller in spring?

The @RestController annotation was introduced in Spring 4.0 to simplify the creation of RESTful web services.

It’s a convenience annotation that combines @Controller and @ResponseBody – which eliminates the need to annotate every request handling method of the controller class with the @ResponseBody annotation..

How does annotation work in spring?

Spring could use its own classloader to load required classes. At runtime, when the class is loaded and Spring determines it has some appropriate annotation, it injects bytecode to add additional properties or behavior to the class.

What is the use of @service annotation in spring?

@Controller annotation is an annotation used in Spring MVC framework (the component of Spring Framework used to implement Web Application). The @Controller annotation indicates that a particular class serves the role of a controller.

What is @service and @component in Spring?

@Component is a generic stereotype for any Spring-managed component or bean. @Repository is a stereotype for the persistence layer. @Service is a stereotype for the service layer. @Controller is a stereotype for the presentation layer (spring-MVC).

What is @configuration annotation in spring?

@Configuration annotation indicates that a class declares one or more @Bean methods and may be processed by the Spring container to generate bean definitions and service requests for those beans at runtime. … This is called Spring Java Config feature (using @Configuration annotation).

What are the annotations used in spring?

Core Spring Framework Annotations@Required. This annotation is applied on bean setter methods. … @Autowired. This annotation is applied on fields, setter methods, and constructors. … @Qualifier. This annotation is used along with @Autowired annotation. … @Configuration. … @ComponentScan. … @Bean. … @Lazy. … @Value.More items…•

What is the difference between @configuration and @component in Spring?

@Component Indicates that an annotated class is a “component”. Such classes are considered as candidates for auto-detection when using annotation-based configuration and classpath scanning. A @Configuration is also a @Component, but a @Component cannot act like a @Configuration.

What is the purpose of @component in Spring?

Spring Component annotation is used to denote a class as Component. It means that Spring framework will autodetect these classes for dependency injection when annotation-based configuration and classpath scanning is used.

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 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 is Repository annotation in spring?

@Repository is a Spring annotation that indicates that the decorated class is a repository. A repository is a mechanism for encapsulating storage, retrieval, and search behavior which emulates a collection of objects.

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 use of @autowired 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 difference between @component and @bean in spring?

@Component auto detects and configures the beans using classpath scanning whereas @Bean explicitly declares a single bean, rather than letting Spring do it automatically.

What does @transactional annotation do?

So when you annotate a method with @Transactional, Spring dynamically creates a proxy that implements the same interface(s) as the class you’re annotating. And when clients make calls into your object, the calls are intercepted and the behaviors injected via the proxy mechanism.