kafka-exercise-Developing-Kafka-Consumer.md

Exercise: Developing Kafka Consumer

1. Read the javadoc of KafkaConsumer to know how to use the Consumer API (to consume messages from Kafka)
2. Create a new Scala/sbt project in IntelliJ IDEA
3. Define dependency for Kafka Clients API library
   1. Use mvnrepository to know the proper entry for kafka-clients dependency
4. Write a Kafka consumer
   1. Name of the object: KafkaConsumerApp
   2. Start with an empty Properties object and fill out the missing properties per exceptions at runtime
   3. Use ConsumerConfig constants (not string values for properties)
   4. Don't forget to close the consumer (so the messages are actually acknowledged to the broker)
5. Run the Kafka consumer
   1. Use kafka-console-producer to produce messages
6. Fix the slf4j logging errors
   1. Define dependencies for slf4j-api and slf4j-log4j12 in build.sbt
   2. Create src/main/resources/log4j.properties as the configuration file
   3. Use Apache Kafka's config/log4j.properties as the sample (4 first non-comment lines)

Duration: 30 mins