Here are the names of jars file that you would require to build custom java implementation and connect to Apache Kafka.
zkclient-0.10.jar
kafka_2.11-2.1.0.jar
kafka-clients-2.1.0.jar
kafka-tools-2.1.0.jar
But as mentioned earlier, propose WmKafkaAdapter to your customer, explain to them the benefits and support they will get and try not reinventing the wheel if something that is already provided OOTB.
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