the test
        try {
            URI u = new URI("host:opa:que?query#fragment");
            System.out.println( u.getPath() );
        } catch (URISyntaxException e) {
            e.printStackTrace();
        }

shows that this URI have null path. (parseServerAuthority has no effect:)
In this case path = 'opa:que'

RFC says that path can't be undefined, it can be empty