Controlling Bean Creation Order with @DependsOn Annotation in Spring Boot

Spring, by default, manages beans’ lifecycle and arranges their initialization order.

But, we can still customize it based on our needs. We can choose either the SmartLifeCycle interface or the @DependsOn annotation for managing initialization order.

@Configuration
@ComponentScan("com.baeldung.dependson")
public class Config {
 
    @Bean
    @DependsOn({"fileReader","fileWriter"})
    public FileProcessor fileProcessor(){
        return new FileProcessor();
    }
    
    @Bean("fileReader")
    public FileReader fileReader() {
        return new FileReader();
    }
    
    @Bean("fileWriter")
    public FileWriter fileWriter() {
        return new FileWriter();
    }   
}

Finally, there are few points which we should take care of while using @DependsOn annotation:

• While using @DependsOn, we must use component-scanning
• If a DependsOn-annotated class is declared via XML, DependsOn annotation metadata is ignored

DependsOnDatabaseInitialization Annotation

Indicate that a bean’s creation and initialization depends upon database initialization having completed. May be used on a bean’s class or its @Bean definition.

References
https://www.baeldung.com/spring-depends-on