Class loading error: ByteArraySerializer could not be found when using KafkaSender.

[maheskrishnan]

I am getting this error when opentelemetry is trying to export traces to Kafka using Kafka sender.

[BatchSpanProcessor_WorkerThread-1] WARN io.opentelemetry.sdk.trace.export.BatchSpanProcessor$Worker - Exporter threw an Exception org.apache.kafka.common.config.ConfigException: Invalid value org.apache.kafka.common.serialization.ByteArraySerializer for configuration key.serializer: Class org.apache.kafka.common.serialization.ByteArraySerializer could not be found.

i am using -Dotel.exporter.jar=myexporter.jar option to use my own custom exporter . myexporter.java does contains the org.apache.kafka.common.serialization.StringSerializer. but when running th application getting this error

StackOverFlow Question: https://stackoverflow.com/questions/65946487/class-not-found-error-in-open-telemetry-exporter

Any help is highly appreciated. Thanks

[jcchavezs]

Is this an issue in our end @anuraaga?

On Fri, 29 Jan 2021, 16:56 Maheswaran Krishnan, notifications@github.com wrote:

[BatchSpanProcessor_WorkerThread-1] WARN io.opentelemetry.sdk.trace.export.BatchSpanProcessor$Worker - Exporter threw an Exception org.apache.kafka.common.config.ConfigException: Invalid value org.apache.kafka.common.serialization.ByteArraySerializer for configuration key.serializer: Class org.apache.kafka.common.serialization.ByteArraySerializer could not be found.

i am using -Dotel.exporter.jar=myexporter.jar option to use my own custom exporter . myexporter.java does contains the org.apache.kafka.common.serialization.StringSerializer. but when running th application getting this error

StackOverFlow Question: https://stackoverflow.com/questions/65946487/class-not-found-error-in-open-telemetry-exporter

Any help is highly appreciated. Thanks

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[maheskrishnan]

Additional context

this is the command line I am using to start my server

java -javaagent:/path/to/opentelemetry-javaagent-all.jar \
      -Dotel.exporter.jar=/path/to/mykafka-exporter-1.0-jar-with-dependencies.jar \
      -Dotel.exporter.zipkin.service.name=sre-client-service-demo       \
      -Dotel.exporter.zipkin.kafka.bootstrap.servers=localhost:9092     \
      -Dotel.exporter.zipkin.kafka.topic=myapp-sre                   \
       -jar ./.out/libs/server.jar server config.yml

1. this otel.exporter.jar=/path/to/mykafka-exporter-1.0-jar-with-dependencies.jar DOES contain the org.apache.kafka.common.serialization.ByteArraySerializer
2. the agent boot loader DOES not have org.apache.kafka.common.serialization.ByteArraySerializer
3. here is the code from Kafka which tries to dynamically loads ByteArraySerializer class using (Thread.currentThread().getContextClassLoader())

    public static ClassLoader getContextOrKafkaClassLoader() {
        ClassLoader cl = Thread.currentThread().getContextClassLoader();
        if (cl == null)
            return getKafkaClassLoader();
        else
            return cl;
    }

4. Thread.currentThread().getContextClassLoader() is Bootstrap agent class loader which does not have ByteArraySerializer.
5. if I change the line "ClassLoader cl = Thread.currentThread().getContextClassLoader();" to "ClassLoader cl = null" it works but Thread.currentThread().getContextClassLoader(); not supposed (in my opinion) to have bootstrap class loader it seems.

[codefromthecrypt]

this is not the opentelemetry project, so if this is still an issue, raise it there. this project does not do any classloader related configuration