Resolving Exception in Thread Main: JOptSimple UnrecognizedOptionException – ZooKeeper Not Recognized

The error “Exception in thread ‘main’ joptsimple.UnrecognizedOptionException: zookeeper is not a recognized option” occurs in Kafka environments when using outdated commands. In newer Kafka versions (2.2 and above), the --zookeeper option has been replaced by --bootstrap-server. This change means that commands referencing ZooKeeper directly will trigger this error. To resolve it, update your commands to use --bootstrap-server instead of --zookeeper.

Cause of the Error

The root cause of the exception in thread main joptsimple.UnrecognizedOptionException: zookeeper is not a recognized option error is the deprecation of the --zookeeper option in newer Kafka versions (2.2 and above). Kafka has replaced the --zookeeper option with the --bootstrap-server option. This change means that commands previously using --zookeeper must now use --bootstrap-server to specify the Kafka server address.

Identifying the Error

To identify the error Exception in thread "main" joptsimple.UnrecognizedOptionException: zookeeper is not a recognized option in logs and error messages:

1. Look for the command: Check the command that was executed. This error often occurs when using an outdated option like --zookeeper in Kafka commands.
2. Error message location: The error typically appears right after the command execution in the logs.
3. Root cause: This error indicates that the --zookeeper option is no longer recognized. Newer Kafka versions (2.2 and above) have replaced it with --bootstrap-server.

Example:

./bin/kafka-console-consumer.sh --topic testTopic --zookeeper localhost:9092

Replace with:

./bin/kafka-console-consumer.sh --topic testTopic --bootstrap-server localhost:9092

Solution

Sure, here are the steps to resolve the UnrecognizedOptionException for ZooKeeper in Kafka:

1. Identify the Command:

   • If you are using a command with --zookeeper, it needs to be updated.

2. Replace --zookeeper with --bootstrap-server:

   • Kafka has deprecated the --zookeeper option in favor of --bootstrap-server.

3. Update Commands:

   • For creating a topic:

     ./bin/kafka-topics.sh --create --topic <topic-name> --bootstrap-server <broker-list> --replication-factor <factor> --partitions <num-partitions>
     

   • For listing topics:

     ./bin/kafka-topics.sh --list --bootstrap-server <broker-list>
     

   • For starting a consumer:

     ./bin/kafka-console-consumer.sh --topic <topic-name> --bootstrap-server <broker-list> --from-beginning
     

   • For starting a producer:

     ./bin/kafka-console-producer.sh --topic <topic-name> --bootstrap-server <broker-list>
     

4. Example:

   • If your original command was:

     ./bin/kafka-console-consumer.sh --topic testTopic --zookeeper localhost:2181
     

   • Update it to:

     ./bin/kafka-console-consumer.sh --topic testTopic --bootstrap-server localhost:9092
     

This should resolve the UnrecognizedOptionException error.

Understanding the ‘Exception in thread “main” joptsimple.UnrecognizedOptionException: zookeeper is not a recognized option’ error

This error is crucial for resolving issues in Kafka environments. It occurs when using outdated commands with the deprecated –zookeeper option, which has been replaced by –bootstrap-server in newer Kafka versions (2.2 and above).

To resolve this issue, it’s essential to stay updated with Kafka’s changes and update commands to use the correct options.

By doing so, you can avoid errors and ensure smooth operation of your Kafka environment.