Essential Java Design Patteren for Kafka Souce and Sink Connectors Development

I am in the phase of pursuing my career as kafka connector developer for real-time analytics and data acquisition. I have been through so many courses either beginners or advance level from udemy.After learning i landed on some conclusion that more or less in all types of maven artifacts for source and sink connectors the build logic is same. Like creation of Final constants , configDefination, source-connectors, sink-connectors, data-model, schema-registry web-client-api , TaskClass etc. in seperate java classes. I want to know the following question from technical geeks of confluent or kafka developer regarding this type of implementation:

1. From which java design pattern strategy it really belongs to Creational, Structural, Behavioral or Architectural Design Pattern?
2. Let suppose if it is creational than why not it could be structural, or if it is structural than why it cannot be Behavioral and so on?
3. Which Exactly sub-design pattern kafka developer and confluent community love to adapt in most of the different kind of scenarios?

I dont know whether the above questions really makes sense? If somene want to catch the fish on his own how one can write its own code following any GoF(Gang of Four) design pattern and contribute in the community of kafka and Confluent. Looking for detailed answer with reference material. Thank you