What Does @Configuration Do In Spring?

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..

Is @configuration Singleton?

The second configuration is totally incorrect because spring will create a singleton bean of SimpleBean, but SimpleBeanConsumer will obtain another instance of SimpleBean which is out of the spring context control. …

What’s the difference between @component @controller @repository and @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 @service annotation in spring?

Spring @Service annotation is used with classes that provide some business functionalities. Spring context will autodetect these classes when annotation-based configuration and classpath scanning is used.

How do you call a bean method in spring?

Spring @Bean Annotation is applied on a method to specify that it returns a bean to be managed by Spring context. Spring Bean annotation is usually declared in Configuration classes methods. In this case, bean methods may reference other @Bean methods in the same class by calling them directly.

What does @bean do 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.

What does the Spring bean lifecycle look like?

Bean life cycle is managed by the spring container. When we run the program then, first of all, the spring container gets started. After that, the container creates the instance of a bean as per the request and then dependencies are injected. And finally, the bean is destroyed when the spring container is closed.

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.

How do I set up annotations in spring?

Starting from Spring 2.5 it became possible to configure the dependency injection using annotations. So instead of using XML to describe a bean wiring, you can move the bean configuration into the component class itself by using annotations on the relevant class, method, or field declaration.

What is @component annotation in spring?

@Component is the most generic Spring annotation. A Java class decorated with @Component is found during classpath scanning and registered in the context as a Spring bean. … Methods decorated with @Bean produce a bean to be managed by the Spring container during configuration stage.

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.

Are all spring beans singletons?

Singleton beans are shared; only one instance of a singleton bean is created per Spring container. Singleton scope is the default scope for a Spring bean. Other bean scopes are: prototype, request, session, global session, and application.

What is the difference between @bean and @autowired?

Annotating @Bean only registers the service as a bean(kind of an Object) in spring application context. … Annotating a variable with @Autowired injects a BookingService bean(i.e Object) from Spring Application Context.

How do you declare a bean in spring?

Spring MVC: How to Declare a Bean in Spring Application?Declaring a bean. In Spring MVC framework, to declare a bean, simply annotate a method with the @Bean annotation. … Step-1. Create new Dynamic Web Project CrunchifySpringMVCFramework in Eclipse. … Step-2. Convert project to Maven project. … Step-3. Open pom. … Step-4. Create new resources folder. … Step-5. … Step-6. … Step-8.More items…•

What is use of @configuration in spring?

@Configuration annotation is used for Spring annotation based configuration. The @Configuration is a marker annotation which 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.

What is the use of @configuration annotation?

Spring @Configuration annotation helps in Spring annotation based configuration. @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.

What is the purpose of @autowired in spring?

The @Autowired annotation provides more fine-grained control over where and how autowiring should be accomplished. The @Autowired annotation can be used to autowire bean on the setter method just like @Required annotation, constructor, a property or methods with arbitrary names and/or multiple arguments.

What is @EnableAutoConfiguration in spring boot?

Annotation Type EnableAutoConfiguration Enable auto-configuration of the Spring Application Context, attempting to guess and configure beans that you are likely to need. Auto-configuration classes are usually applied based on your classpath and what beans you have defined. For example, if you have tomcat-embedded.