[Support #XZX-274428]: using new runtimeConfig with toolsUI 2.2.17.21

Hi Ken:

In case you havent solved this yet, make sure your class is public and it has a 
no-arg constructor. Let me know if its still a problem.

I dont understand the abstract thing, I assume some new method got added you 
need to implement.

Ticket Details
===================
Ticket ID: XZX-274428
Department: Support THREDDS
Priority: Emergency
Status: Open