Verifying issues addressed by this issue: spring-cloud/spring-cloud-stream-binder-kafka#682 and this SO thread: https://stackoverflow.com/questions/55929162/spring-cloud-stream-generates-unnecessary-complex-kafka-topologies-why/55943420#55943420
Go to the root of the repository.
Make sure you have Kafka broker running. The application expects it to be on defaults (localhost:9092). If thats not the case, change the configuration.
./mvnw clean package
Run the application (CLI or IDE).
Watch the logs on the startup to examine the topology generated.