Java Kafka consumer

The following program is a simple Java consumer which consumes data from topic test. Please make sure data is already available in the mentioned topic otherwise no record will be consumed.

import org.apache.kafka.clients.consumer.*;
import org.apache.kafka.common.TopicPartition;
import org.apache.log4j.Logger;

import java.util.*;

public class DemoConsumer {
    private static final Logger log = Logger.getLogger(DemoConsumer.class);

    public static void main(String[] args) throws Exception {

        String topic = "test1";
        List<String> topicList = new ArrayList<>();
        topicList.add(topic);
        Properties consumerProperties = new Properties();
        consumerProperties.put("bootstrap.servers", "localhost:9092");
        consumerProperties.put("group.id", "Demo_Group");
        consumerProperties...