I can not get the value from the yaml file , Spring Boot Kotlin Environment

I am trying different attempts to get the value from the yaml file, but no matter what I try, it stays null.

application.yml file

demo-control:
  environment: ${ENVIRONMENT:prod}
  managedRegions: ${MANAGED_REGIONS:us-east-1}

Component Class Attempt:1

import org.springframework.beans.factory.annotation.Autowired
import org.springframework.beans.factory.annotation.Value
import org.springframework.context.annotation.Configuration
import org.springframework.stereotype.Component


@Component
class AppProperties(@Value("\${demo-control.managedRegions}") private val managedRegions: String)

Component Class Attempt 2

    @Component
    class AppProperties {
        @Value("\${demo-control.managedRegions}")
        lateinit var managedRegions: String
    }

class that I would like to use the value

class AwsProvider(
    private val creds: AwsCredentials,
    @Value("\${demo-control.managedRegions}")
    private val managedRegions: String? = null // Attempt1
) : CloudProvider {


Attempt1
@Value("\${demo-control.managedRegions}")
private val managedRegions: String? = null

Attempt2
@Value("\${demo-control.managedRegions}")
lateinit var region:String

Using the @Value annotation is a straightforward approach to get config values from application.yml, similar to what you have tried above.

I have used the annotation to inject the config value to a Controller in a sample Spring Boot app which works as expected. The relevant code is shared below:

import org.slf4j.LoggerFactory
import org.springframework.beans.factory.annotation.Value
...

@RestController
@RequestMapping("v1/orders")
class OrdersController {

    @Value("\${demo-control.managedRegions}")
    private lateinit var managedRegions: String

    private final val log = LoggerFactory.getLogger(this.javaClass)

    @GetMapping(produces = [MediaType.APPLICATION_JSON_VALUE])
    fun getOrders(): List<OrderDto> {
        log.info("demo-control.managedRegions: $managedRegions")
        ...
    }

And here is the log that prints the demo-control.managedRegions config value:

2024-10-31T16:10:00.504+05:30 INFO 1834 --- [nio-8080-exec-3] c.d.s.api.OrdersController: demo-control.managedRegions: us-east-1

The application.yml file:

demo-control:
  environment: ${ENVIRONMENT:prod}
  managedRegions: ${MANAGED_REGIONS:us-east-1}

The Spring Boot application:

@SpringBootApplication
class SpringDemoApplication

fun main(args: Array<String>) {
    runApplication<SpringDemoApplication>(*args)
}

The build.gradle with Spring Boot plugins and dependency:

plugins {
    id("org.springframework.boot")
    id("io.spring.dependency-management")
    kotlin("jvm")
    kotlin("plugin.spring")
}

implementation("org.springframework.boot:spring-boot-starter-web")