RPC连接错误

在使用RPC客户端和服务端连接时，出现

log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Exception in thread "main" java.lang.reflect.UndeclaredThrowableException
    at com.sun.proxy.$Proxy4.login(Unknown Source)
    at cn.edu.nupt.Hadoop.rpc.LoginController.main(LoginController.java:13)
Caused by: org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.ipc.RpcServerException): Unknown protocol: cn.edu.nupt.Hadoop.rpc.LoginServiceInterface
    at org.apache.hadoop.ipc.WritableRpcEngine$Server$WritableRpcInvoker.call(WritableRpcEngine.java:493)
    at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:969)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2049)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2045)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:422)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1657)
    at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2043)

    at org.apache.hadoop.ipc.Client.call(Client.java:1475)
    at org.apache.hadoop.ipc.Client.call(Client.java:1412)
    at org.apache.hadoop.ipc.WritableRpcEngine$Invoker.invoke(WritableRpcEngine.java:243)
    ... 2 more

一般就是，连接名或者端口的问题，还有是两个端的包命名空间不太一样，

对比两个端进行统一就可以解决。