[KAFKA-9093] NullPointerException in KafkaConsumer with group.instance.id

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.3.0
• Fix Version/s: 2.3.2
• Component/s: clients
• Assignee: huxihx
• Reporter: Rolef Heinrich
• Created: 24/Oct/19 08:40
• Updated: 01/Nov/19 02:09
• Resolved: 01/Nov/19 02:09

Description

When using group.instance.id=myUniqId[0], the KafkaConsumer's constructor throws a NullpointerException in close():

 

Caused by: java.lang.NullPointerException
 at org.apache.kafka.clients.consumer.KafkaConsumer.close(KafkaConsumer.java:2204)
 at org.apache.kafka.clients.consumer.KafkaConsumer.<init>(KafkaConsumer.java:825)
 at org.apache.kafka.clients.consumer.KafkaConsumer.<init>(KafkaConsumer.java:664)
 at org.apache.kafka.clients.consumer.KafkaConsumer.<init>(KafkaConsumer.java:644)

It turns out that the exception is thrown because the log member is not yet initialized (still null) in the constructor when the original exception is handled. The original exception is thrown before log is initailized.

The side effect of this error is, that close does does not cleanup resources as clean is supposed to do.

The used consumer properties for reference:

 

key.deserializer=com.ibm.streamsx.kafka.serialization....
request.timeout.ms=25000
value.deserializer=com.ibm.streamsx.kafka.serialization....
client.dns.lookup=use_all_dns_ips
metadata.max.age.ms=2000
enable.auto.commit=false
group.instance.id=myUniqId[0]
max.poll.interval.ms=300000
group.id=consumer-0
metric.reporters=com.ibm.streamsx.kafka.clients.consum...
reconnect.backoff.max.ms=10000
bootstrap.servers=localhost:9092
max.poll.records=50
session.timeout.ms=20000
client.id=C-J37-ReceivedMessages[0]
allow.auto.create.topics=false
metrics.sample.window.ms=10000
retry.backoff.ms=500
reconnect.backoff.ms=250

Expected behaviour: throw exception indicating that something is wrong with the chosen group.instance.id.

The documentation does not tell anything about valid values for group.instance.id.

Reproduce:

 

 

 
import java.util.Properties;
import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.clients.consumer.KafkaConsumer;

public class Main {
    public static void main(String[] args) {
        Properties props = new Properties();
        props.put (ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
        props.put (ConsumerConfig.GROUP_ID_CONFIG, "group-Id1");
        props.put (ConsumerConfig.GROUP_INSTANCE_ID_CONFIG, "myUniqId[0]");
        props.put (ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
        props.put (ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
        KafkaConsumer c = new KafkaConsumer (props);
    }
}


Exception in thread "main" java.lang.NullPointerException
	at org.apache.kafka.clients.consumer.KafkaConsumer.close(KafkaConsumer.java:2204)
	at org.apache.kafka.clients.consumer.KafkaConsumer.<init>(KafkaConsumer.java:825)
	at org.apache.kafka.clients.consumer.KafkaConsumer.<init>(KafkaConsumer.java:664)
	at org.apache.kafka.clients.consumer.KafkaConsumer.<init>(KafkaConsumer.java:644)
	at Main.main(Main.java:15)

 

Issue Links

• links to: GitHub Pull Request #7590