```import com.fasterxml.jackson.annotation.JsonUnwrapped import com.fasterxml.jackson.databind.Objec...

# jackson-kotlin

[reik.schatz]

import com.fasterxml.jackson.annotation.JsonUnwrapped
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.kotlin.KotlinModule
import org.assertj.core.api.Assertions.assertThat
import org.junit.jupiter.api.Test

data class Container(@JsonUnwrapped val row: Map<String, Any?>)

class JsonUnwrappedTest {

    @Test
    fun `should unwrap`() {
        val row = Container(row = mapOf("foo" to "bar"))

        val objectMapper = ObjectMapper()
        objectMapper.registerModule(KotlinModule())

        val json = objectMapper.writeValueAsString(row)
        assertThat(json).isEqualTo("""{"foo": "bar"}""") // fails
    }
}

[diesieben07]

This has nothing to do with Kotlin. JsonUnwrapped only works for POJOs, not Maps. You can use a combination of JsonAnyGetter and JsonAnySetter to achieve something similar, seen here:
https://stackoverflow.com/a/18043785

[reik.schatz]

@diesieben07 oh, thanks a lot. I wasn’t aware of this