With Spring\u2019s auto-scanning feature, it automatically detects various beans defined in our application.<\/strong> We usually annotate our beans using one of the available Spring annotations \u2013 @Component, @Repository, @Service, @Controller<\/em>.<\/p>\n On detecting the bean, Spring simply registers it into the ApplicationContext<\/em>.<\/p>\n In this quick tutorial, we\u2019ll look at the difference between @Component, @Repository, and, @Service<\/em> Spring annotations.<\/p>\n We can use @Component<\/em> annotation to mark a bean as a Spring-managed component. In other words, it\u2019s a generic stereotype for any Spring-managed component<\/strong>.<\/p>\n We can enable an auto-scan using <context:component-scan> <\/em>tag. During auto-scan, Spring will scan and register all beans marked with a @Component<\/em> annotation:<\/p>\n @Repository<\/em> annotation is a specialization over @Component<\/em> annotation:<\/p>\n Since @Repository<\/em> is a type of @Component<\/em>, Spring also auto-scans and registers them.<\/p>\n @Repository<\/em> is a stereotype for the persistence layer. Its job is to catch all persistence related exceptions and rethrow them as a Spring DataAccessException<\/em>.<\/strong> For this, we should configure PersistenceExceptionTranslationPostProcessor<\/em> in our application context:<\/p>\n This bean post processor adds an advisor to all beans marked with @Repository<\/em>. The advisor\u2019s responsibility is to translate the platform-specific exceptions to the Spring\u2019s unified unchecked exceptions.<\/p>\n Just like @Repository, @Service<\/em> is another specialization of @Component<\/em>:<\/p>\n Just like @Repository, @Service<\/em> is also a type of @Component<\/em>. That means Spring will also automatically detect such beans.<\/p>\n The @Service<\/em> annotation represents that our bean holds some business logic. <\/strong>Till date, it doesn\u2019t provide any specific behavior over @Component<\/em>.<\/p>\n Still, we should annotate the service-layer beans with the @Service<\/em> annotation to make our intent clear.<\/strong> Additionally, we never know if someday Spring chooses to add some specific functionality to it.<\/p>\n Let\u2019s quickly sum up the differences between @Component, @Repository <\/em>and, @Service:<\/em><\/p>\n In this mini-tutorial, we have learned the difference between the popular Spring annotations \u2013 @Component, @Service, and @Repository.<\/em><\/p>\n To conclude, we should always prefer using the annotations based on their specific layer conventions.<\/p>\n@Component:<\/em><\/h3>\n
\n@Component\npublic class Employee {\n ...\n \n}\n<\/pre>\n@Repository:<\/em><\/h3>\n
\n@Component\npublic @interface Repository {\n}\n<\/pre>\n\n<bean class=\n \"org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor\"\/>\n<\/pre>\n
@Service<\/em>:<\/h3>\n
\n@Component\npublic @interface Service {\n}\n<\/pre>\nDifferences in NutShell:<\/h3>\n
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Conclusion:<\/h3>\n