java.lang.NoClassDefFoundError: on Android 6

Question

App is working fine on Nexus6P running android 9. I am trying to run application on Nexus 5 (Android 6) but getting the following error:

Caused by: java.lang.NoClassDefFoundError: org.openmined.syft.networking.datamodels.syft.AuthenticationResponseSerializer$deserialize$data$1$1
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at org.openmined.syft.networking.datamodels.syft.AuthenticationResponseSerializer$deserialize$data$1.invoke(AuthenticationDataModels.kt:66)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at org.openmined.syft.networking.datamodels.syft.AuthenticationResponseSerializer$deserialize$data$1.invoke(AuthenticationDataModels.kt:55)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at kotlinx.serialization.json.JsonElementBuildersKt.json(JsonElementBuilders.kt:14)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at org.openmined.syft.networking.datamodels.syft.AuthenticationResponseSerializer.deserialize(AuthenticationDataModels.kt:65)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at org.openmined.syft.networking.datamodels.syft.AuthenticationResponseSerializer.deserialize(AuthenticationDataModels.kt:55)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at kotlinx.serialization.json.internal.PolymorphicKt.decodeSerializableValuePolymorphic(Polymorphic.kt:34)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at kotlinx.serialization.json.internal.StreamingJsonInput.decodeSerializableValue(StreamingJsonInput.kt:33)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at kotlinx.serialization.CoreKt.decode(Core.kt:80)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at kotlinx.serialization.json.Json.parse(Json.kt:126)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at kotlinx.serialization.json.Json$Companion.parse(Json.kt:178)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at com.jakewharton.retrofit2.converter.kotlinx.serialization.Serializer$FromString.fromResponseBody(Serializer.kt:18)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at com.jakewharton.retrofit2.converter.kotlinx.serialization.DeserializationStrategyConverter.convert(DeserializationStrategyConverter.kt:11)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at com.jakewharton.retrofit2.converter.kotlinx.serialization.DeserializationStrategyConverter.convert(DeserializationStrategyConverter.kt:7)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at retrofit2.OkHttpCall.parseResponse(OkHttpCall.java:225)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at retrofit2.OkHttpCall.execute(OkHttpCall.java:188)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at retrofit2.adapter.rxjava2.CallExecuteObservable.subscribeActual(CallExecuteObservable.java:45)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at io.reactivex.Observable.subscribe(Observable.java:12267)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at retrofit2.adapter.rxjava2.BodyObservable.subscribeActual(BodyObservable.java:34)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at io.reactivex.Observable.subscribe(Observable.java:12267)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at io.reactivex.internal.operators.observable.ObservableSingleSingle.subscribeActual(ObservableSingleSingle.java:35)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at io.reactivex.Single.subscribe(Single.java:3603)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at io.reactivex.internal.operators.single.SingleSubscribeOn$SubscribeOnObserver.run(SingleSubscribeOn.java:89)
05-08 12:57:26.776 15456-15592/org.openmined.syft.demo W/System.err:     at io.reactivex.Scheduler$DisposeTask.run(Scheduler.java:578)
05-08 12:57:26.777 15456-15592/org.openmined.syft.demo W/System.err:     at io.reactivex.internal.schedulers.ScheduledRunnable.run(ScheduledRunnable.java:66)
05-08 12:57:26.777 15456-15592/org.openmined.syft.demo W/System.err:    ... 6 more

DataModel

@Serializer(forClass = AuthenticationResponse::class)
internal class AuthenticationResponseSerializer : KSerializer<AuthenticationResponse> {
    private val json = Json(JsonConfiguration.Stable)
    override val descriptor: SerialDescriptor
        get() = SerialClassDescImpl("AuthResponseSerializer")

    override fun deserialize(decoder: Decoder): AuthenticationResponse {
        val input = decoder as? JsonInput
                    ?: throw SerializationException("This class can be loaded only by Json")
        val response = input.decodeJson() as? JsonObject
                       ?: throw SerializationException("Expected JsonObject")
        val data = json {
            response.forEach { key, value ->
                if (key != "status")
                    key to value
            }
        }
        return if (response.getPrimitive("status").content == AUTH_SUCCESS)
            json.parse(
                AuthenticationResponse.AuthenticationSuccess.serializer(),
                data.toString()
            )
        else
            json.parse(AuthenticationResponse.AuthenticationError.serializer(), data.toString())
    }

    override fun serialize(encoder: Encoder, obj: AuthenticationResponse) {
        val output = encoder as? JsonOutput
                     ?: throw SerializationException("This class can be saved only by Json")
        when (obj) {
            is AuthenticationResponse.AuthenticationSuccess -> output.encodeJson(
                json.toJson(
                    AuthenticationResponse.AuthenticationSuccess.serializer(),
                    obj
                )
            )
            is AuthenticationResponse.AuthenticationError ->
                output.encodeJson(
                    json.toJson(
                        AuthenticationResponse.AuthenticationError.serializer(),
                        obj
                    )
                )
        }
    }
}

Can anyone please comment what can be the issue? kotlinx.serialization libraries are not supported on Android 6?

Thanks

What's your Kotlin version? Kotlin versions before 1.4.0 are not supported by the stable release of Kotlin serialization. — Victor Pozdnyakov, May 08 '21 at 08:47
@VictorPozdnyakov Same application is running fine on Android 9. — Mustansar Saeed, May 08 '21 at 08:50
And what is your kotlin compiler version? (https://github.com/Kotlin/kotlinx.serialization#setup) — Victor Pozdnyakov, May 08 '21 at 08:54

Victor Pozdnyakov · Answer 1 · 2021-05-08T09:46:22.943

Try to add annotation @Keep to your Serializable class.

@Serializable
@Keep
class AuthenticationResponse {
// ...
}...

Compiler may think that the code is unused. @Keep denotes that the annotated element should not be removed when the code is minified at build time

Another solutions

to your proguard-rules.pro (more info):

kotlinx-serialization-json specific. Add this if you have java.lang.NoClassDefFoundError kotlinx.serialization.json.JsonObjectSerializer

-keepclassmembers class kotlinx.serialization.json.** {
    *** Companion;
}
-keepclasseswithmembers class kotlinx.serialization.json.** {
    kotlinx.serialization.KSerializer serializer(...);
}

mismatches between Kotlin and Kotlinx.serialization
and another link

`minifyEnabled` field is `false` in the `build.gradle` configuration — Mustansar Saeed, May 08 '21 at 11:00

java.lang.NoClassDefFoundError: on Android 6

1 Answers1