What is the @bean annotation?
One of the most important annotations in spring is the @Bean annotation which 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. This annotation is also a part of the spring core framework.
What is @configuration and @bean in Spring?
Annotating a class with the @Configuration indicates that the class can be used by the Spring IoC container as a source of bean definitions. The @Bean annotation tells Spring that a method annotated with @Bean will return an object that should be registered as a bean in the Spring application context.
What is @bean used for?
@Bean is a method-level annotation and a direct analog of the XML <bean/> element. The annotation supports most of the attributes offered by <bean/> , such as: init-method , destroy-method , autowiring , lazy-init , dependency-check , depends-on and scope .
How do Springs find beans?
The first step of defining Spring Beans is by adding the right annotation — @Component or @Service or @Repository . However, Spring does not know about the bean unless it knows where to search for it. This part of “telling Spring where to search” is called a Component Scan.
What is @bean and @autowired?
@Bean is just for the metadata definition to create the bean(equivalent to tag). @Autowired is to inject the dependancy into a bean(equivalent to ref XML tag/attribute).
Where we can use @bean annotation?
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.
Can we use @bean without @configuration?
@Bean methods may also be declared within classes that are not annotated with @Configuration. For example, bean methods may be declared in a @Component class or even in a plain old class. In such cases, a @Bean method will get processed in a so-called ‘lite’ mode.
What is difference between @configuration and @EnableAutoConfiguration?
How They Differ. The main difference between these annotations is that @ComponentScan scans for Spring components while @EnableAutoConfiguration is used for auto-configuring beans present in the classpath in Spring Boot applications.
Can we use @qualifier and @bean together?
NOTE: if you are creating bean with @Bean, it will be injected byType if there is duplicates then it will injected byName. we no need to mention @Bean(name=”bmwDriver”) . so you can directly use qualifier(“bmwDriver”) wherever you need in classes.
What is the difference between @component and @bean?
@Component is a class-level annotation, but @Bean is at the method level, so @Component is only an option when a class’s source code is editable. @Bean can always be used, but it’s more verbose. @Component is compatible with Spring’s auto-detection, but @Bean requires manual class instantiation.
What is difference between @component and @bean in Spring?
What is @component and bean?
@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.
What is difference between @bean and @component?
What is the difference between @bean and configuration?
@Bean is an annotation based configuration and hence is used in @Configuration based class. This is an explicit way of defining a bean and is also used on the methods defined in configuration class.
Can we use both @SpringBootApplication and @EnableAutoConfiguration?
You don’t need to add it manually, spring will add it internally for you based on the annotation you provide. Actually the @SpringBootApplication annotation is equivalent to using @Configuration , @EnableAutoConfiguration and @ComponentScan with their default attributes.
What is @component and @ComponentScan?
@Component and @ComponentScan are for different purposes. @Component indicates that a class might be a candidate for creating a bean. It’s like putting a hand up. @ComponentScan is searching packages for Components.
What is @autowired and @qualifier?
Both @Autowired and @Qualifier are two different methods of autowire annotations that are used to achieve dependency injection in Spring. You can use @Qualifier along with @Autowired to help Spring Framework find the right bean to autowire.
Can 2 beans have same name in Spring?
Spring beans are identified by their names within an ApplicationContext. Therefore, bean overriding is a default behavior that happens when we define a bean within an ApplicationContext that has the same name as another bean. It works by simply replacing the former bean in case of a name conflict.
Is @component and @bean same?
Can we use @bean in @component class?
@Willa yes, @Bean can be used in inside a class annotiated with @Component . “You can use the @Bean annotation in a @Configuration-annotated or in a @Component-annotated class.” docs.spring.io/spring-framework/docs/current/reference/html/…
Is @SpringBootApplication mandatory?
Uses. It’s not mandatory to put @SpringBootApplication to create a Spring Boot application, you can still use @Configuration and @EnableAutoConfiguration individually as shown in the example given in the next point.
What is difference between @SpringBootApplication and EnableAutoConfiguration?
SpringBootApplication combines of 3 annotations: @Configuration, used for Java-based configuration on Spring framework, @ComponentScan to enable component scanning of components, and @EnableAutoConfiguration itself, which is used to allow for auto-configuration in Spring Boot application.
What is @configuration @EnableAutoConfiguration and ComponentScan?
The main difference between these annotations is that @ComponentScan scans for Spring components while @EnableAutoConfiguration is used for auto-configuring beans present in the classpath in Spring Boot applications. Now, let’s go through them in more detail.
What is difference between @qualifier and primary?
We use @Qualifier in Spring to autowire a specific bean among same type of beans, where as @Primary is used to give high preference to the specific bean among multiple beans of same type to inject to a bean.
What is @qualifier in Spring boot?
The @Qualifier annotation in Spring is used to differentiate a bean among the same type of bean objects. If we have more than one bean of the same type and want to wire only one of them then use the @Qualifier annotation along with @Autowired to specify which exact bean will be wired.