The most common cause of such issues is usually class loading. You probably have added the flink-connector-kafka also to flink-dist/libs. But the connector is only meant to be bundled with your job jar afaik. Right now, you have the Kafka classes loaded in the user code classloader and in the system classloader of Flink itself.
On Fri, Nov 27, 2020 at 12:24 AM Kevin Kwon <fsw0...@gmail.com> wrote: > Hi community, I'm testing out 1.12-SNAPSHOT in master branch > > I built my application with library 'flink-connector-kafka' but when I > start the app, I get > > Caused by: org.apache.kafka.common.KafkaException: class > org.apache.kafka.common.serialization.ByteArrayDeserializer is not an > instance of org.apache.kafka.common.serialization.Deserializer > > while constructing KafkaConsumer class. Is this normal behavior? > -- Arvid Heise | Senior Java Developer <https://www.ververica.com/> Follow us @VervericaData -- Join Flink Forward <https://flink-forward.org/> - The Apache Flink Conference Stream Processing | Event Driven | Real Time -- Ververica GmbH | Invalidenstrasse 115, 10115 Berlin, Germany -- Ververica GmbH Registered at Amtsgericht Charlottenburg: HRB 158244 B Managing Directors: Timothy Alexander Steinert, Yip Park Tung Jason, Ji (Toni) Cheng