private synchronized void listenRpc(QrConfig cfg) {
        Spec listenSpec = new Spec(cfg.rpc().port());
        try {
            acceptor = supervisor.listen(listenSpec);
            slobrokRegistrator = registerInSlobrok(cfg, acceptor.port());
        } catch (ListenFailedException e) {
            throw new RuntimeException("Could not create rpc server listening on " + listenSpec, e);
        }
    }
Do not delete this method even if it's empty.
Calling this methods forces this class to be loaded,
which runs the static block.
container-disc/src/main/java/com/yahoo/container/jdisc/ConfiguredApplication.java