Oliver, seems that the new implementation of JenkinsController#start does work only for a small subset of controllers:

            try {
                populateJenkinsHome(new File(JenkinsController.class.getResource("jenkins_updates").toURI()), false);
            } catch (URISyntaxException ex) {
                throw new AssertionError(ex);
            }

Most controllers throw an exception in populateJenkinsHome. Moreover, if using the jutServer.sh command, then the resource "jenkins_updates" is within a jar and the conversion to a URI fails with an exception.

I already removed the exception for the TYPE=existing implementation: de8d094