### ReferenceConfig#init , at line 307
change : prifix -> prefix
<img width="746" alt="1" src="https://user-images.githubusercontent.com/6971152/35309902-a22d3ed2-00e9-11e8-9928-e394b9e3d632.png">

### by the way,  ReferenceConfig#setInterface , at line 476
it's no need to cast null to String
<img width="903" alt="2" src="https://user-images.githubusercontent.com/6971152/35309908-b09e4a92-00e9-11e8-9725-8e6ff8071370.png">

isJvmRefer = true;
            } else {
                isJvmRefer = false;
            }
        } else {
            isJvmRefer = isInjvm().booleanValue();
        }
        if (isJvmRefer) {
            URL url = new URL(Constants.LOCAL_PROTOCOL, NetUtils.LOCALHOST, 0, interfaceClass.getName()).addParameters(map);
            invoker = refprotocol.refer(interfaceClass, url);
            if (logger.isInfoEnabled()) {
                logger.info("Using injvm service " + interfaceClass.getName());
            }
        } else {
            if (url != null && url.length() > 0) { 
                String[] us = Constants.SEMICOLON_SPLIT_PATTERN.split(url);
                if (us != null && us.length > 0) {
                    for (String u : us) {
                        URL url = URL.valueOf(u);
                        if (url.getPath() == null || url.getPath().length() == 0) {
                            url = url.setPath(interfaceName);
                        }
                        if (Constants.REGISTRY_PROTOCOL.equals(url.getProtocol())) {
                            urls.add(url.addParameterAndEncoded(Constants.REFER_KEY, StringUtils.toQueryString(map)));
                        } else {
                            urls.add(ClusterUtils.mergeUrl(url, map));
                        }
                    }
                }
            } else {