@Component annotation in Spring Boot - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the @Component annotation in Spring Boot?

The <code>@Component</code> annotation tells Spring to create and manage an instance of the class as a bean. It makes the class available for dependency injection.

beginner

How does Spring Boot find classes annotated with @Component?

Spring Boot scans the packages specified in the application for classes with @Component and automatically registers them as beans in the application context.

beginner

Can @Component be used on interfaces or only on classes?

<code>@Component</code> should be used on classes, not interfaces, because Spring creates an instance of the class to manage as a bean.

intermediate

What is the difference between @Component and @Service annotations?

@Service is a specialized form of @Component used to mark service layer classes. Functionally they are similar, but @Service adds semantic meaning.

intermediate

How can you give a custom name to a bean created with @Component?

You can specify a name by passing a string value to @Component("customName"). This name can be used to refer to the bean in the Spring context.

What does the @Component annotation do in Spring Boot?

A Defines a database entity

B Specifies a REST controller

C Marks a class as a Spring-managed bean

D Configures application properties

@Component marks a class so Spring creates and manages it as a bean.

Where should you place the @Component annotation?

A On classes you want Spring to manage

B On interfaces only

C On methods only

D On configuration files

@Component is used on classes to tell Spring to create beans from them.

Which annotation is a specialized form of @Component for service classes?

A @Repository

B @Service

C @Controller

D @Configuration

@Service is a specialized @Component for service layer classes.

How does Spring Boot find classes annotated with @Component?

A By scanning specified packages automatically

B By manual registration only

C By reading XML files

D By runtime user input

Spring Boot scans packages to find @Component classes and registers them automatically.

How can you assign a custom name to a bean created with @Component?

A Using <code>@Autowired("name")</code>

B Using <code>@Bean(name="name")</code>

C Using <code>@Service(name="name")</code>

D Using <code>@Component("name")</code>

You can pass a string to @Component to name the bean.

Explain what the @Component annotation does in Spring Boot and why it is useful.

Think about how Spring knows which classes to create and manage.

Describe how you can customize the name of a bean created with @Component and why you might want to do that.

Consider how Spring identifies beans in the application context.