SpringBoot Spring boot GraalVM empty object serialization

hi

this is a sample demo using spring boot 3.2.0, kotlin 1.9.20, java 21

data class Person(
    val id: Int = 0,
    val name: String = ""
)

@SpringBootApplication
@ImportRuntimeHints(MyHintsRegistration::class)
class SpringbootDemoApplication {

    @Bean
    fun routes() = coRouter {
        GET("/") { ok().bodyValueAndAwait("hi") }
        GET("/{name}") { ok().bodyValueAndAwait(Person(id = Random.nextInt(), name = it.pathVariable("name")))}
    }
}

class MyHintsRegistration : RuntimeHintsRegistrar {
    override fun registerHints(hints: RuntimeHints, classLoader: ClassLoader?) {
        hints.reflection().registerType<Person>()
    }
}

fun main() {
    runApplication<SpringbootDemoApplication>()
}

when generated a native graalvm executable and try to call endpoind (curl, httpie, postman) i receive an empty object {} (expect a person serialize object) what wrong here ?

Comment From: bclozel

Registering the type itself just makes it available in the native image for loading the class by its name. Here, the serialization framework will need to look at fields and invoke methods.

This bit is covered in the reference documentation here: https://docs.spring.io/spring-framework/reference/core/aot.html#aot.hints.register-reflection-for-binding

For more questions, please use StackOverflow.

Thanks!