Producer Fails to Send Data and NullPointerException Is Thrown

Hello, everyone! 

I will share with you how to deal with the problem that producer fails to send data and NullPointerException is thrown when using Kafka.

Symptom

When Producer sends data to Kafka, the client throws NullPointerException.

Possible Causes

1. The Kafka service is abnormal.

2. The Jass and Keytab files configured on the Producer client are incorrect.

Fault Locating

The possible reasons why Producer fails to send data to Kafka may be related to Producer or Kafka.

1. On the FusionInsight Manager page, choose Services > Kafka Status. The current status of the Kafka cluster is Good and the monitoring indicators show no errors.

2. Check the Producer client log. The log contains NullPointerException information, as shown in the following.

   

   Alternatively, the log contains only NullPointerException information and no stack

   information. The problem is caused by JDK self-protection. If much information is printed for the same stack, the JDK self-protection is triggered and stack information is no longer printed.

   

3. Check the Producer client log. The log contains Failed to configure SaslClientAuthenticator information, as shown in the following.

   

4. Therefore, KafkaChannel fails to be created due to authentication failure. The KafkaChannel obtained through the channel (key) is empty and NullPointerException is excessively printed. The preceding log shows that authentication failure is due to an empty password. The reason why the password is empty may be that the password does not match the username.

5. Check the Jaas and Keytab files. The principal parameter is set to stream in the Jaas file.

   

   The principal parameter is set to zmk_kafka in the user.keytab file.

   The principal in the Jaas file does not correspond to that in the user.keytab file.

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