[Question] Probably I somehow incorrectly configure the application, but when I get it I get an error

[BorzdeG]

source: https://github.com/BorzdeG/samples-kotlin-subprojects/tree/kotlinx.serialization

Exception in thread "main" java.lang.IllegalArgumentException: JSON at 5: Expected '{, kind: CLASS'
	at kotlinx.serialization.json.JSON$Companion.fail(JSON.kt:190)
	at kotlinx.serialization.json.JSON$Companion.require(JSON.kt:186)
	at kotlinx.serialization.json.JSON$Companion.access$require(JSON.kt:54)
	at kotlinx.serialization.json.JSON$JsonInput.readBegin(JSON.kt:349)
	at demo.common.ChildModelSerializer.load(ChildModel.kt:25)
	at demo.common.ChildModelSerializer.load(ChildModel.kt:9)
	at kotlinx.serialization.KInput.readSerializableValue(Serialization.kt:243)
	at kotlinx.serialization.ElementValueInput.readSerializableElementValue(Serialization.kt:438)
	at demo.common.ParentModelSerializer.load(ParentModel.kt:35)
	at demo.common.ParentModelSerializer.load(ParentModel.kt:15)
	at kotlinx.serialization.KInput.read(Serialization.kt:209)
	at kotlinx.serialization.json.JSON.parse(JSON.kt:47)
	at kotlinx.serialization.json.JSON$Companion.parse(JSON.kt:57)
	at demo.client.jvm.ClientJvmKt.main(ClientJvm.kt:28)

[sandwwraith]

The correct approach to write deserializing code manually is to use input returned from readBegin. Also you always need to call readElement to determine current element to read (in json, they can go in other order comparing to what you have in class) So code for your ChildModel will look like this:

override fun load(input: KInput): ChildModel {
		val newInput = input.readBegin(serialClassDesc)
                val i = newInput.readElement(serialClassDesc)
                check(i == 0) // if you have more than one field, make "when" here
		val cf = newInput.readStringElementValue(serialClassDesc, 0)
		newInput.readEnd(serialClassDesc)
		return ChildModel(cf = cf)
	}

[sandwwraith]

But I'm wondering why you're trying to write the same code that plugin will generate for you...

[JoaquimLey]

It might not be the case for @BorzdeG, but I got a similar error.
I'm writing about my exp. since it might help others coming here with a similar situation.

---

In my case, I was trying to parse my object from an empty String, so make sure your String is not null and that in fact, matches your Model.class

e.g:

If

class FooUserModel(name: String)

Is updated to

class FooUserModel(firstName: String, lastName: String)

And the model you have stored/trying to parse doesn't match 1-to-1, this is the logical error to be thrown, so watch out for that.