{"id":295,"date":"2025-05-27T13:00:00","date_gmt":"2025-05-27T13:00:00","guid":{"rendered":"https:\/\/springmasteryhub.com\/?p=295"},"modified":"2025-04-22T18:03:04","modified_gmt":"2025-04-22T18:03:04","slug":"understanding-the-configuration-annotation-in-spring","status":"publish","type":"post","link":"https:\/\/springmasteryhub.com\/?p=295","title":{"rendered":"Understanding the @Configuration Annotation in Spring"},"content":{"rendered":"\n

The @Configuration<\/code> annotation indicates to Spring that the class has one or more @Bean<\/code> methods. When starting the application context, Spring will look to these classes to load the Spring IoC container with the beans you define in those methods.<\/p>\n\n\n\n

It allows you to create custom beans and perform configurations (like when you use Spring Security) so that everything is ready to go when the application starts.<\/p>\n\n\n\n

It’s a really simple and powerful annotation, often combined with other annotations.<\/p>\n\n\n\n

Let’s see it in practice.<\/h3>\n\n\n\n

@Configuration<\/code> It is a class-level annotation. So we can define a configuration class and create some bean methods like this:<\/p>\n\n\n\n

<\/circle><\/circle><\/circle><\/g><\/svg><\/span><\/path><\/path><\/svg><\/span>
import<\/span> org.springframework.context.annotation.Bean;<\/span><\/span>\nimport<\/span> org.springframework.context.annotation.Configuration;<\/span><\/span>\n<\/span>\n@<\/span>Configuration<\/span><\/span>\npublic<\/span> <\/span>class<\/span> <\/span>MyConfiguration<\/span> {<\/span><\/span>\n<\/span>\n    <\/span>private<\/span> <\/span>static<\/span> <\/span>final<\/span> <\/span>Logger<\/span> log <\/span>=<\/span> LoggerFactory.<\/span>getLogger<\/span>(MyConfiguration.class);<\/span><\/span>\n<\/span>\n    @<\/span>Bean<\/span><\/span>\n    <\/span>public<\/span> <\/span>MyBean<\/span> <\/span>myBean<\/span>() {<\/span><\/span>\n        log.<\/span>info<\/span>(<\/span>"<\/span>Creating my custom bean<\/span>"<\/span>);<\/span><\/span>\n        <\/span>return<\/span> <\/span>new<\/span> <\/span>MyBean<\/span>();<\/span><\/span>\n    }<\/span><\/span>\n}<\/span><\/span>\n<\/span>\nclass<\/span> <\/span>MyBean<\/span> {<\/span><\/span>\n    <\/span>\/\/ bean properties and methods<\/span><\/span>\n}<\/span><\/span>\n<\/span>\n@<\/span>SpringBootApplication<\/span><\/span>\npublic<\/span> <\/span>class<\/span> <\/span>Main<\/span> {<\/span><\/span>\n<\/span>\n    <\/span>public<\/span> <\/span>static<\/span> <\/span>void<\/span> <\/span>main<\/span>(<\/span>String<\/span>[] <\/span>args<\/span>) {<\/span><\/span>\n        SpringApplication.<\/span>run<\/span>(Main.class, args);<\/span><\/span>\n    }<\/span><\/span>\n}<\/span><\/span>\n<\/span>\n<\/span><\/code><\/pre><\/div>\n\n\n\n
Spring will load your configurations by default if they\u2019re in the same package as your application\u2019s main. Or if it\u2019s in the configurations, it’s in sub-packages from your application\u2019s main.<\/p>\n\n\n\n
For example:<\/p>\n\n\n\n
If your main is in org.example.application<\/code> And your configurations are located in packages in the same package tree, for example, org.example.application.config<\/code> Spring will automatically scan and read these configurations for you.<\/p>\n\n\n\n
But if it is not reading your configuration class because they are not in the same package tree, you could use the @Import<\/code> annotation in your application, or use the @ComponentScan annotation to point to Spring, where those configurations are.<\/p>\n\n\n\n
Now you know how to configure your Spring applications using the @Configuration<\/code> annotation.<\/p>\n\n\n\n
If you like this topic, make sure to follow me. In the following days, I\u2019ll be explaining more about Spring annotations! Stay tuned!<\/p>\n\n\n\n
Willian Moya (@WillianFMoya) \/ X (twitter.com)<\/a><\/p>\n\n\n\n
Willian Ferreira Moya | LinkedIn<\/a><\/p>\n\n\n\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
The @Configuration annotation indicates to Spring that the class has one or more @Bean methods. When starting the application context, Spring will look to these classes to load the Spring IoC container with the beans you define in those methods. It allows you to create custom beans and perform configurations (like when you use Spring […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[3,6],"tags":[13,18,22,23,24],"class_list":["post-295","post","type-post","status-publish","format-standard","hentry","category-java","category-spring","tag-java","tag-programming","tag-spring-boot","tag-spring-framework","tag-springboot"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=\/wp\/v2\/posts\/295","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=295"}],"version-history":[{"count":1,"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=\/wp\/v2\/posts\/295\/revisions"}],"predecessor-version":[{"id":296,"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=\/wp\/v2\/posts\/295\/revisions\/296"}],"wp:attachment":[{"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=295"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=295"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=295"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}