Receiver class does not define or inherit an implementation of the resolved method 'abstract boolean getDevelopmentMode()' - kotlin

Question

I'm trying to run local server with KTOR and to cover it with tests. I wrote some code and after writing some tests, the tests successfully raised the local server and passed. However, if I try to start a local server, I get this error
Exception in thread "main" java.lang.AbstractMethodError: Receiver
class io.ktor.server.engine.ApplicationEngineEnvironmentReloading does
not define or inherit an implementation of the resolved method
'abstract boolean getDevelopmentMode()' of interface
io.ktor.application.ApplicationEnvironment.
I attach the code and the stack trace from below
server.kt
import io.ktor.application.*
import io.ktor.features.*
import io.ktor.gson.*
import io.ktor.http.*
import io.ktor.response.*
import io.ktor.routing.*
import kotlinx.serialization.SerialName
import kotlinx.serialization.Serializable
fun main(args: Array<String>): Unit = io.ktor.server.netty.EngineMain.main(args)
fun Application.module(testing: Boolean = false) {
install(ContentNegotiation) {
gson()
}
routing {
val controller = Controller()
get("/converter{from}{to}") {
try {
val fromCurrency = call.request.queryParameters["from"]
val toCurrency = call.request.queryParameters["to"]
val rate = controller.converter(fromCurrency, toCurrency)
val response = Response(
"1 $fromCurrency = $rate $toCurrency",
null
)
call.respond(HttpStatusCode.OK, response)
} catch (e: ControllerException) {
val response = Response(
null,
e.message
)
call.respond(HttpStatusCode.BadRequest, response)
}
}
get {
call.respond(HttpStatusCode.NotFound, Response())
}
}
}
#Serializable
data class Response(
#SerialName("converterResponse")
val converterResponse: String? = null,
#SerialName("errorMessage")
val errorMessage: String? = null
)
converterTest.kt
import com.google.gson.Gson
import io.ktor.application.*
import io.ktor.http.*
import io.ktor.server.testing.*
import kotlin.test.Test
import kotlin.test.assertEquals
class ConverterTest {
#Test
fun `Identical Correct Currencies`() {
withTestApplication(Application::module) {
handleRequest(HttpMethod.Get, "/converter?from=USD&to=USD").apply {
assertEquals(HttpStatusCode.OK, response.status())
val expectedResponse = Response("1 USD = 1 USD")
assertEquals(
Gson().toJson(expectedResponse),
response.content
)
}
}
}
}
stacktrace
Exception in thread "main" java.lang.AbstractMethodError: Receiver class io.ktor.server.engine.ApplicationEngineEnvironmentReloading does not define or inherit an implementation of the resolved method 'abstract boolean getDevelopmentMode()' of interface io.ktor.application.ApplicationEnvironment.
at io.ktor.application.Application.<init>(Application.kt:20)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.instantiateAndConfigureApplication(ApplicationEngineEnvironmentReloading.kt:269)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.createApplication(ApplicationEngineEnvironmentReloading.kt:125)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.start(ApplicationEngineEnvironmentReloading.kt:245)
at io.ktor.server.netty.NettyApplicationEngine.start(NettyApplicationEngine.kt:126)
at io.ktor.server.netty.EngineMain.main(EngineMain.kt:26)
at ServerKt.main(server.kt:11)
build.gradle
import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
plugins {
kotlin("jvm") version "1.5.30" // or kotlin("multiplatform") or any other kotlin plugin
application
}
group = "me.admin"
version = "1.0-SNAPSHOT"
repositories {
jcenter()
mavenCentral()
maven { url = uri("https://dl.bintray.com/kotlin/kotlinx") }
maven { url = uri("https://dl.bintray.com/kotlin/ktor") }
}
dependencies {
val kotlin_version = "1.5.30"
val ktor_version = "1.6.3"
implementation("io.ktor:ktor-server-netty:1.4.0")
implementation("io.ktor:ktor-client-cio:1.4.0")
implementation("io.ktor:ktor-html-builder:1.4.0")
implementation("io.ktor:ktor-client-serialization:1.3.2-1.4-M2")
implementation("org.jetbrains.kotlinx:kotlinx-html-jvm:0.7.2")
implementation("org.slf4j:slf4j-api:2.0.0-alpha5")
implementation("org.jetbrains.kotlinx:kotlinx-serialization-core:1.0.0-RC")
implementation(kotlin("stdlib-jdk8"))
testImplementation("org.jetbrains.kotlin:kotlin-test:$kotlin_version")
testImplementation("io.ktor:ktor-server-test-host:$ktor_version")
implementation("io.ktor:ktor-gson:$ktor_version")
}
tasks.test {
useJUnitPlatform()
}
tasks.withType<KotlinCompile> {
kotlinOptions.jvmTarget = "1.8"
}
application {
mainClassName = "ServerKt"
}
val compileKotlin: KotlinCompile by tasks
compileKotlin.kotlinOptions {
jvmTarget = "1.8"
}
val compileTestKotlin: KotlinCompile by tasks
compileTestKotlin.kotlinOptions {
jvmTarget = "1.8"
}

Answer 1

The dependency io.ktor:ktor-server-netty:1.4.0 causes the AbstractMethodError. To fix it just use the same version for all Ktor dependencies:
implementation("io.ktor:ktor-server-netty:$ktor_version")
implementation("io.ktor:ktor-client-cio:$ktor_version")
implementation("io.ktor:ktor-html-builder:$ktor_version")
implementation("io.ktor:ktor-client-serialization:$ktor_version")