Text '' could not be parsed at index 0

[Jookus]

Since a few days I am getting the following error when using the FBA Inventory API with the Java sdk without specifying a startDateTime. If I set any startDateTime, everything is fine, but I need to go throw the whole inventory database and as far as I understood the documentation startDateTime should be optional for that purpose.

    java.time.format.DateTimeParseException: Text '' could not be parsed at index 0

	at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1949)
	at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1851)
	at java.time.OffsetDateTime.parse(OffsetDateTime.java:402)
	at com.amazon.sellingpartner.JSON$OffsetDateTimeTypeAdapter.read(JSON.java:215)
	at com.amazon.sellingpartner.JSON$OffsetDateTimeTypeAdapter.read(JSON.java:179)
	at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:129)
	at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:220)
	at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.read(TypeAdapterRuntimeTypeWrapper.java:41)
	at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:82)
	at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:61)
	at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:129)
	at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:220)
	at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:129)
	at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:220)
	at com.google.gson.Gson.fromJson(Gson.java:887)
	at com.google.gson.Gson.fromJson(Gson.java:852)
	at com.google.gson.Gson.fromJson(Gson.java:801)
	at com.amazon.sellingpartner.JSON.deserialize(JSON.java:137)
	at com.amazon.sellingpartner.ApiClient.deserialize(ApiClient.java:760)
	at com.amazon.sellingpartner.ApiClient.handleResponse(ApiClient.java:963)
	at com.amazon.sellingpartner.ApiClient.execute(ApiClient.java:890)
	at com.amazon.sellingpartner.api.FbaInventoryApi.getInventorySummariesWithHttpInfo(FbaInventoryApi.java:195)
	at com.amazon.sellingpartner.api.FbaInventoryApi.getInventorySummaries(FbaInventoryApi.java:175)

Update:
While digging deeper I found out, that I recently created a new catalog item that has not been updated yet.
Here is the raw response from the api:

     {
            "asin": "XXXXX",
            "fnSku": "XXXXX",
            "sellerSku": "XXXXX",
            "condition": "NewItem",
            "inventoryDetails": {"fulfillableQuantity":0,"inboundWorkingQuantity":0,"inboundShippedQuantity":0,"inboundReceivingQuantity":0,"reservedQuantity":{"totalReservedQuantity":0,"pendingCustomerOrderQuantity":0,"pendingTransshipmentQuantity":0,"fcProcessingQuantity":0},"researchingQuantity":{"totalResearchingQuantity":0,"researchingQuantityBreakdown":[]},"unfulfillableQuantity":{"totalUnfulfillableQuantity":0,"customerDamagedQuantity":0,"warehouseDamagedQuantity":0,"distributorDamagedQuantity":0,"carrierDamagedQuantity":0,"defectiveQuantity":0,"expiredQuantity":0},"futureSupplyQuantity":{"reservedFutureSupplyQuantity":0,"futureSupplyBuyableQuantity":0}},
            "lastUpdatedTime": "",  <------------------------------------ EMPTY STRING <-----------------
            "productName": "XXXXXXXXXXXXXXXXXXXXXXX",
            "totalQuantity": 0
        }

In this case 'lastUpdatedTime' is empty and causes the crash in ApiClient class when trying to deserialize to the GetInventorySummariesResponse class.
Other people have the same issue with different sdks: Link

I think the sdk should be able to handle these empty variables.

[Jookus]

As a workaround in the java sdk you can find the OffsetDateTimeTypeAdapter in the generated JSON.java class and change the following function:

 @Override
        public OffsetDateTime read(JsonReader in) throws IOException {
            switch (in.peek()) {
                case NULL:
                    in.nextNull();
                    return null;
                default:
                    String date = in.nextString();
                    if (date.length() == 0) return null;  <------- this is new to skip empty values
                    if (date.endsWith("+0000")) {
                        date = date.substring(0, date.length()-5) + "Z";
                    }
                    return OffsetDateTime.parse(date, formatter);
            }
        }

[smargoli2]

@Jookus , thanks! The C# code is generated differently. I tried messing with the JsonSerializerSettings but there is no property for the JSON serializer to ignore null values when deserializing. I will try to submit a PR to OpenAPIGenerator (I am using that generator) to add such an option (i.e. GenerateOptionalPropertiesAsNullable).

[lvyuanj]

@Jookus, The reason for this problem is that when the response data is returned, the time field is an empty string, and the source code only handles null and non-empty times. No processing is done on time data that returns null characters. If is a Java SDK, find the corresponding JSON class, find the corresponding OffsetDateTimeTypeAdapter the read method to do the processing of an empty string