kotlinx.serialization.MissingFieldException: Field 'X' is required for type with serial name but it was missing Error in kotlin - json

Question

I am making a dictionary application and I have my own json dataset inside the asset file. I read from this data set for the first time and save it to the room, and then I read from the room for other times. However, I am encountering this error.
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.enestigli.dictionaryapp, PID: 1868
kotlinx.serialization.MissingFieldException: Field 'example' is required for type with serial name 'com.enestigli.dictionaryapp.data.locale.datamodel.Idioms', but it was missing
at kotlinx.serialization.internal.PluginExceptionsKt.throwMissingFieldException(PluginExceptions.kt:20)
at com.enestigli.dictionaryapp.data.locale.datamodel.Idioms.<init>(Idiom.kt:28)
at com.enestigli.dictionaryapp.data.locale.datamodel.Idioms$$serializer.deserialize(Idiom.kt:28)
at com.enestigli.dictionaryapp.data.locale.datamodel.Idioms$$serializer.deserialize(Idiom.kt:28)
at kotlinx.serialization.json.internal.PolymorphicKt.decodeSerializableValuePolymorphic(Polymorphic.kt:59)
at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableValue(StreamingJsonDecoder.kt:36)
at kotlinx.serialization.encoding.AbstractDecoder.decodeSerializableValue(AbstractDecoder.kt:43)
at kotlinx.serialization.encoding.AbstractDecoder.decodeSerializableElement(AbstractDecoder.kt:70)
at kotlinx.serialization.encoding.CompositeDecoder$DefaultImpls.decodeSerializableElement$default(Decoding.kt:535)
at kotlinx.serialization.internal.ListLikeSerializer.readElement(CollectionSerializers.kt:80)
at kotlinx.serialization.internal.AbstractCollectionSerializer.readElement$default(CollectionSerializers.kt:51)
at kotlinx.serialization.internal.AbstractCollectionSerializer.merge(CollectionSerializers.kt:36)
at kotlinx.serialization.internal.AbstractCollectionSerializer.deserialize(CollectionSerializers.kt:43)
at kotlinx.serialization.json.internal.PolymorphicKt.decodeSerializableValuePolymorphic(Polymorphic.kt:59)
at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableValue(StreamingJsonDecoder.kt:36)
at kotlinx.serialization.encoding.AbstractDecoder.decodeSerializableValue(AbstractDecoder.kt:43)
at kotlinx.serialization.encoding.AbstractDecoder.decodeSerializableElement(AbstractDecoder.kt:70)
at com.enestigli.dictionaryapp.data.locale.datamodel.IdiomItem$$serializer.deserialize(Idiom.kt:15)
at com.enestigli.dictionaryapp.data.locale.datamodel.IdiomItem$$serializer.deserialize(Idiom.kt:15)
at kotlinx.serialization.json.internal.PolymorphicKt.decodeSerializableValuePolymorphic(Polymorphic.kt:59)
at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableValue(StreamingJsonDecoder.kt:36)
at kotlinx.serialization.encoding.AbstractDecoder.decodeSerializableValue(AbstractDecoder.kt:43)
at kotlinx.serialization.encoding.AbstractDecoder.decodeSerializableElement(AbstractDecoder.kt:70)
at kotlinx.serialization.encoding.CompositeDecoder$DefaultImpls.decodeSerializableElement$default(Decoding.kt:535)
at kotlinx.serialization.internal.ListLikeSerializer.readElement(CollectionSerializers.kt:80)
at kotlinx.serialization.internal.AbstractCollectionSerializer.readElement$default(CollectionSerializers.kt:51)
at kotlinx.serialization.internal.AbstractCollectionSerializer.merge(CollectionSerializers.kt:36)
at kotlinx.serialization.internal.AbstractCollectionSerializer.deserialize(CollectionSerializers.kt:43)
at kotlinx.serialization.json.internal.PolymorphicKt.decodeSerializableValuePolymorphic(Polymorphic.kt:59)
at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableValue(StreamingJsonDecoder.kt:36)
at com.enestigli.dictionaryapp.data.locale.datamodel.IdiomDataModel$$serializer.deserialize-zhuhEdE(Idiom.kt:8)
at com.enestigli.dictionaryapp.data.locale.datamodel.IdiomDataModel$$serializer.deserialize(Idiom.kt:8)
at kotlinx.serialization.json.internal.PolymorphicKt.decodeSerializableValuePolymorphic(Polymorphic.kt:59)
at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableValue(StreamingJsonDecoder.kt:36)
at kotlinx.serialization.json.Json.decodeFromString(Json.kt:100)
at com.enestigli.dictionaryapp.data.locale.datasource.AssetDataSource.getIdioms-zhuhEdE(AssetsDataSource.kt:84)
E/AndroidRuntime: at com.enestigli.dictionaryapp.data.repository.IdiomsRepositoryImpl.initData(IdiomsRepositoryImpl.kt:21)
at com.enestigli.dictionaryapp.domain.use_case.idiom.insert.InsertIdiomsUseCase.initIdiomData(InsertIdiomsUseCase.kt:12)
at com.enestigli.dictionaryapp.presentation.SplashScreen.SplashScreenViewModel$insertAllDataToRoomDb$1.invokeSuspend(SplashScreenViewModel.kt:38)
at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
at android.os.Handler.handleCallback(Handler.java:942)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loopOnce(Looper.java:201)
at android.os.Looper.loop(Looper.java:288)
at android.app.ActivityThread.main(ActivityThread.java:7898)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:936)
Suppressed: kotlinx.coroutines.DiagnosticCoroutineContextException: [StandaloneCoroutine{Cancelling}#5aeb15c, Dispatchers.Main.immediate]
my json dataset looks like this
[
{
"letter": "A",
"idioms": [
{
"idiom": "above board",
"meaning": "If something is above board, it's been done in a legal and honest way.",
"examples": [
"I'm sure the deal was completely above board as I know James well and he'd never do anything illegal or corrupt.",
"The minister claimed all the appointments were above board and denied claims that some positions had been given to his friends."
]
},
{
"idiom": "above the law",
"meaning": "If someone is above the law, they are not subject to the laws of a society.",
"examples": [
"Just because his father is a rich and powerful man, he seems to think he's above the law and he can do whatever he likes.",
"In a democracy, no-one is above the law - not even a president or a prime-minister."
]
},
{
"idiom": "Achilles' heel",
"meaning": "An Achilles' heel is a weakness that could result in failure.",
"examples": [
"He's a good golfer, but his Achilles' heel is his putting and it's often made him lose matches.",
"The country's dependence on imported oil could prove to be its Achilles' heel if prices keep on rising."
]
},
My Data Model
#JvmInline
#Serializable
value class IdiomDataModel(
val allData: List<IdiomItem>
)
#Serializable
data class IdiomItem(
val letter: String,
val idioms: List<Idioms>
) {
fun toEntity() = IdiomEntity(
letter = letter,
idioms = idioms
)
}
#Serializable
data class Idioms(
val idiom: String,
val meaning: String,
val example: List<String>
)
Entity
#Entity(tableName = "idioms")
data class IdiomEntity(
#ColumnInfo(name = "letter") val letter:String,
#ColumnInfo(name = "idioms") val idioms:List<Idioms>,
#PrimaryKey(autoGenerate = true) val uid:Int? = null
)
I think the val example: List<String> in the Idioms data class is from this part. Could it be that this does not exactly match the example list in the Json dataset?

Answer 1

In your Idioms data class, rename example to examples and it should work.
Old:
#Serializable
data class Idioms(
val idiom: String,
val meaning: String,
val example: List<String>
)
New
#Serializable
data class Idioms(
val idiom: String,
val meaning: String,
val examples: List<String>
)