OpenAPI Code for Watson X Assistant

I am in need of a Java developer who can create OpenAPI code for Watson X Assistant extensions. This code should facilitate communication between the assistant and both Google Calendar and Outlook Calendar.

Key requirements and expectations:
- The code should allow the assistant to take user input and have that input modify existing events in Google Calendar and Outlook Calendar. It should also provide an export feature to Excel/Sheets.
- I will handle the authentication with Google and Outlook Calendar APIs separately, so the code does not need to manage this.

Ideal skills and experience for this project:
- Proficiency in Java programming language, as the code needs to be written in Java.
- Prior experience with OpenAPI, and specifically in developing extensions for Watson X Assistant, would be highly beneficial.
- Familiarity with Google Calendar and Outlook Calendar APIs is a plus, but not essential as long as you can quickly understand their documentation.

Please note: This project does not involve handling of authentication, beyond understanding how the code will interact with authenticated services.