How to Write a Kafka Connector with Proper Configuration Handling

This post details how to correctly handle configuration for Kafka Connectors. It explains the use of `ConfigDef` to define configuration parameters, including types, importance, and default values. It introduces `ConfigDef.Validator` for validating individual configuration values and `ConfigDef.Recommender` for suggesting valid values, especially when they depend on other configurations. The post also describes how the `validate()` method in the `Connector` class is used by Kafka Connect to validate configurations before instance creation and how to override it for complex inter-config dependencies. It highlights the role of these mechanisms in GUI applications like Confluent Control Center.