How do I use multiple consumers in Kafka?

Question

I am a new student studying Kafka and I\'ve run into some fundamental issues with understanding multiple consumers that articles, documentations, etc. have not been too helpful

Answer 1

I think your problem lies with the auto.offset.reset property. When a new consumer reads from a partition and there's no previous committed offset, the auto.offset.reset property is used to decide what the starting offset should be. If you set it to "largest" (the default) you start reading at the latest (last) message. If you set it to "smallest" you get the first available message.

So add:

properties.put("auto.offset.reset", "smallest");

and try again.

* edit *

"smallest" and "largest" were deprecated a while back. You should use "earliest" or "latest" now. Any questions, check the docs