What is the use of @Configuration and @Bean annotations in Spring?

Question

Accepted Answer

@Configuration and @Bean are Spring annotations used for Java-based configuration. They allow developers to define and manage Spring Beans without using XML configuration files.

Key Points:
• @Configuration marks a class as a source of bean definitions for the Spring IoC container.
• Spring scans a @Configuration class and processes all methods annotated with @Bean.
• @Bean is applied to a method to indicate that the returned object should be managed as a Spring Bean.
• Beans created using @Bean are registered in the Spring container and can be injected into other components.
• Java-based configuration provides better type safety, readability, and maintainability compared to XML configuration.

Example:
A configuration class can define a DataSource or Service object using @Bean, and Spring will automatically create and manage that object throughout the application lifecycle.

Code Example:

```
@Configuration
public class AppConfig {

@Bean
    public UserService userService() {
        return new UserService();
    }
}
```
Interview Tip:
A concise interview answer is:

"@Configuration marks a class as a Spring configuration class, while @Bean is used to define objects that should be managed by the Spring IoC container. Spring creates and manages these beans and makes them available for dependency injection."