Stopping SoapUI threads completely

I'm using soapUI as a library to test some web services but once I finish all tests looks like there is something that stops my tests from terminating

I'm basically creating WsdlProjects from xml and running WsdlTestCase with run method.

I switched to soapuitestrunner and the same thing is happening to me.

When I run tests in the log the following appears

09:19:46,735 DEBUG [SoapUIMultiThreadedHttpConnectionManager$SoapUIDefaultClientConnection] Sending request: POST /sbms/ws/AnnwynService HTTP/1.1
09:19:47,298 DEBUG [SoapUIMultiThreadedHttpConnectionManager$SoapUIDefaultClientConnection] Receiving response: HTTP/1.1 500 Internal Server Error
09:19:47,301 DEBUG [HttpClientSupport$SoapUIHttpClient] Connection can be kept alive indefinitely

Then the test ends and after a while the following appears

09:20:19,809 DEBUG [SoapUIMultiThreadedHttpConnectionManager$SoapUIDefaultClientConnection] Connection closed

Do I need to manually shut down some process?