### 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">

private static final long serialVersionUID = -5864351140409987595L;
    private static final Protocol refprotocol = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension();
    private static final Cluster cluster = ExtensionLoader.getExtensionLoader(Cluster.class).getAdaptiveExtension();
    private static final ProxyFactory proxyFactory = ExtensionLoader.getExtensionLoader(ProxyFactory.class).getAdaptiveExtension();
    private final List<URL> urls = new ArrayList<URL>();
    
    private String interfaceName;
    private Class<?> interfaceClass;
    
    private String client;
    
    private String url;
    
    private List<MethodConfig> methods;
    
    private ConsumerConfig consumer;
    private String protocol;
    
    private transient volatile T ref;
    private transient volatile Invoker<?> invoker;
    private transient volatile boolean initialized;
    private transient volatile boolean destroyed;
    @SuppressWarnings("unused")
    private final Object finalizerGuardian = new Object() {