I too am trying to call SoapUI from Java, wanting to run certain test cases with certain properties and then be able to determine what failed where (get a report).
I see that you have followed a similar path to me (based on the examples from https://support.smartbear.com/readyapi/docs/testing/integrations/junit.html) - I have a couple of questions:
1) Did you ever get a satisfactory answer from Smartbear?
2) Where to I import SoapUIPro.SoapUIProCore from? Or has this disappeared from recent versions?
The problem is that the Smartbear API documentation is out of date.
Seems to be an ongoing issue (since 2010 or longer).
As a developer, I know that documentation is the last job I want to do, but as a user (albeit a fairly technical user) it is the first thing I need.