> For the complete documentation index, see [llms.txt](https://dev117uday.gitbook.io/notes-md/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dev117uday.gitbook.io/notes-md/spring-boot/spring-basics/important-spring-things.md).

# Important Spring Things

just things

## ApplicationRunner

* Automatically run method when Spring Boot starts

```java
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;

import lombok.extern.slf4j.Slf4j;

@Component
@Slf4j
public class ConfigRunner implements ApplicationRunner {

    @Override
    public void run(ApplicationArguments args) throws Exception {
        log.info("XXXXXXXXXXX ============ XXXXXXXXXXXXXX");
    }
    
}
```