Apache Kafka Study Guide 2026
Everything you need to pass the Apache Kafka exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📚 Apache Kafka Topics to Study (23)
✍️ Sample Apache Kafka Questions & Answers
1. What is a 'changelog topic' in Kafka Streams?
Kafka Streams writes all state store updates to a changelog topic so that state can be restored from Kafka if a task migrates to another instance.
2. Which CLI tool is used to list, describe, and reset consumer group offsets in Kafka?
kafka-consumer-groups.sh manages consumer group metadata including listing groups, describing lag, resetting offsets, and deleting groups.
3. What is a 'session window' in Kafka Streams?
Session windows group events for a key into a session as long as the gap between consecutive events is less than the inactivity gap timeout.
4. Can you decrease the number of partitions in an existing Kafka topic?
Kafka does not support decreasing the partition count of an existing topic because it would require redistributing data and break ordering guarantees.
5. What does a 'stream-table join' in Kafka Streams do?
A stream-table join looks up the latest KTable value for a record's key and enriches the stream record with that value in real time.
6. Which Kafka CLI tool is used to create a new topic?
kafka-topics.sh with the --create flag is the standard tool for creating new Kafka topics from the command line.