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Explanation

In Spring Boot, a Bean is an object managed by the Spring IoC (Inversion of Control) container.

Code:

@Component
public class UserService {
}

Explanation

Singleton Bean: Only one instance is created for the entire application. This is the default bean scope in Spring.

Code:

@Component
@Scope("singleton")
public class UserService {
}

Explanation

Prototype Bean: A new object is created every time the bean is requested from the Spring container.

Code:

@Component
@Scope("prototype")
public class UserService {
}

Explanation

Request Bean: A new bean instance is created for every HTTP request in a web application.

Code:

@Component
@Scope(value =
 WebApplicationContext.SCOPE_REQUEST)
public class RequestBean {
}

Explanation

Beans can also be created using stereotypes and @Bean annotation inside configuration classes.

Code:

@Service
public class OrderService {
}

@Configuration
public class AppConfig {

    @Bean
    public UserService userService() {
        return new UserService();
    }
}