Serialization error in Serdes while running Streams Application - serialization

Question

I am writing an application that processes an incoming record of coordinates and monitors them for entry or exit in defined geofences. Intermediately, I am maintaining a state whether the current coordinate is inside/outside a specific geofence using aggregation.
Below is the stack trace of the error while running this:
Exception in thread "geofence-events-990be707-d44d-410d-a8a7-b2a3b90cb84f-StreamThread-1" org.apache.kafka.streams.errors.StreamsException: Exception caught in process. taskId=0_0, processor=KSTREAM-SOURCE-0000000003, topic=vehicle-sensor-data, partition=0, offset=0
at org.apache.kafka.streams.processor.internals.StreamTask.process(StreamTask.java:367)
at org.apache.kafka.streams.processor.internals.AssignedStreamsTasks.process(AssignedStreamsTasks.java:104)
at org.apache.kafka.streams.processor.internals.TaskManager.process(TaskManager.java:413)
at org.apache.kafka.streams.processor.internals.StreamThread.runOnce(StreamThread.java:862)
at org.apache.kafka.streams.processor.internals.StreamThread.runLoop(StreamThread.java:777)
at org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:747)
Caused by: org.apache.kafka.streams.errors.StreamsException: A serializer (key: org.apache.kafka.common.serialization.StringSerializer / value: org.apache.kafka.common.serialization.StringSerializer) is not compatible to the actual key or value type (key type: java.lang.String / value type: com.loconav.GeoFenceDTO). Change the default Serdes in StreamConfig or provide correct Serdes via method parameters.
at org.apache.kafka.streams.processor.internals.SinkNode.process(SinkNode.java:94)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:146)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:129)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:93)
at org.apache.kafka.streams.kstream.internals.KStreamFilter$KStreamFilterProcessor.process(KStreamFilter.java:43)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:115)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:146)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:129)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:93)
at org.apache.kafka.streams.kstream.internals.KStreamMap$KStreamMapProcessor.process(KStreamMap.java:42)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:115)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:146)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:129)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:93)
at org.apache.kafka.streams.kstream.internals.KStreamPeek$KStreamPeekProcessor.process(KStreamPeek.java:44)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:115)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:146)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:129)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:93)
at org.apache.kafka.streams.kstream.internals.KStreamFlatMapValues$KStreamFlatMapValuesProcessor.process(KStreamFlatMapValues.java:42)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:115)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:146)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:129)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:93)
at org.apache.kafka.streams.kstream.internals.KStreamKTableJoinProcessor.process(KStreamKTableJoinProcessor.java:73)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:115)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:146)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:129)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:93)
at org.apache.kafka.streams.kstream.internals.KStreamFlatMapValues$KStreamFlatMapValuesProcessor.process(KStreamFlatMapValues.java:42)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:115)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:146)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:129)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:93)
at org.apache.kafka.streams.kstream.internals.KStreamMap$KStreamMapProcessor.process(KStreamMap.java:42)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:115)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:146)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:129)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:93)
at org.apache.kafka.streams.processor.internals.SourceNode.process(SourceNode.java:84)
at org.apache.kafka.streams.processor.internals.StreamTask.process(StreamTask.java:351)
... 5 more
Caused by: java.lang.ClassCastException: class com.loconav.GeoFenceDTO cannot be cast to class java.lang.String (com.loconav.GeoFenceDTO is in unnamed module of loader 'app'; java.lang.String is in module java.base of loader 'bootstrap')
at org.apache.kafka.common.serialization.StringSerializer.serialize(StringSerializer.java:28)
at org.apache.kafka.common.serialization.Serializer.serialize(Serializer.java:60)
at org.apache.kafka.streams.processor.internals.RecordCollectorImpl.send(RecordCollectorImpl.java:157)
at org.apache.kafka.streams.processor.internals.RecordCollectorImpl.send(RecordCollectorImpl.java:101)
at org.apache.kafka.streams.processor.internals.SinkNode.process(SinkNode.java:89)
... 45 more
I wrote a peek after flatMapValues and the first record gets printed and then this exception occurs. Below is the topology code
vehicleGeoFences
.flatMapValues(
(readOnlyKey, value) -> {
List<GeoFenceDTO> geoFenceDTOS = new ArrayList<>();
// some logic
return geoFenceDTOS;
})
.groupBy((key, value) -> value.getGeofenceId() + "," + value.getVehicleId())
.aggregate(
GeoFenceDTO::new,
(key, value, aggregate) -> {
//setting values
return geofenceDTO;
},
Materialized.with(Serdes.String(), getGeofenceDTOValueSerde()))
.toStream()
.mapValues(
(readOnlyKey, value) -> {
// changing object
})
.to(
Topics.VEHICLE_EVENTS.name(),
Produced.with(vehicleEventsKeySerde, vehicleEventsValueSerde));
I have written a custom Serde on GeofenceDTO than uses jackson ObjectMapper to convert object to bytes and vice-versa. Somehow it looks parameters provided in the Materialized are not being picked. The default key value Serde for the application is StringSerde.
Help appreciated. TIA. I tried changing custom object to Avro generated but same error persisted.