Weird RMI exception

The program of server A accesses the RMI service published by the program of server B, and a strange exception is reported. I have never seen it before. It needs to be carefully analyzed:

2013-08-22 15:02:46,942 [com.plat.rmi.time.RmiLogTimeImpl] - [ERROR] Failed to send digest.
org.springframework.remoting.RemoteConnectFailureException: Could not connect to remote service [rmi://172.29.0.73:1100/SummaryService]; nested exception is java.rmi.ConnectException: Connection refused to host: ; nested exception is:
        java.net.ConnectException: Connection refused
        at org.springframework.remoting.rmi.RmiClientInterceptorUtils.convertRmiAccessException(RmiClientInterceptorUtils.java:189)
        at org.springframework.remoting.rmi.RmiClientInterceptor.doInvoke(RmiClientInterceptor.java:347)
        at org.springframework.remoting.rmi.RmiClientInterceptor.refreshAndRetry(RmiClientInterceptor.java:330)
        at org.springframework.remoting.rmi.RmiClientInterceptor.handleRemoteConnectFailure(RmiClientInterceptor.java:306)
        at org.springframework.remoting.rmi.RmiClientInterceptor.invoke(RmiClientInterceptor.java:262)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
        at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
        at com.sun.proxy.$Proxy28.push(Unknown Source)
        at com.plat.rmi.time.RmiLogTimeImpl.update(Unknown Source)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:309)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
        at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)

Special attention: the configuration of hostname in /etc/hosts and /etc/sysconfig/network in Linux.