I have a service export as hessian mode,like:

interface srv{
Hashtable getBeans();
void read(String f);
}
the first can work ,the second call can't ,why?

in server: exception as:
java.io.IOException: java.lang.reflect.InvocationTargetException
at com.caucho.hessian.io.JavaDeserializer.readMap(Jav aDeserializer.java:119)
at com.caucho.hessian.io.HessianInput.readObject(Hess ianInput.java:662)
at com.caucho.hessian.server.HessianSkeleton.invoke(H essianSkeleton.java:181)
at org.springframework.remoting.caucho.HessianService Exporter.handleRequest(HessianServiceExporter.java :84)
at org.springframework.web.servlet.mvc.SimpleControll erHandlerAdapter.handle(SimpleControllerHandlerAda pter.java:44)
at org.springframework.web.servlet.DispatcherServlet. doService(DispatcherServlet.java:535)
at org.springframework.web.servlet.FrameworkServlet.s erviceWrapper(FrameworkServlet.java:366)
at org.springframework.web.servlet.FrameworkServlet.d oPost(FrameworkServlet.java:326)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:717)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:810)
at org.apache.catalina.core.ApplicationFilterChain.in ternalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.do Filter(ApplicationFilterChain.java:157)
at net.sf.acegisecurity.ui.AbstractIntegrationFilter. doFilter(AbstractIntegrationFilter.java:170)
at net.sf.acegisecurity.util.FilterToBeanProxy.doFilt er(FilterToBeanProxy.java:88)
at org.apache.catalina.core.ApplicationFilterChain.in ternalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.do Filter(ApplicationFilterChain.java:157)
at net.sf.acegisecurity.ui.basicauth.BasicProcessingF ilter.doFilter(BasicProcessingFilter.java:199)
at net.sf.acegisecurity.util.FilterToBeanProxy.doFilt er(FilterToBeanProxy.java:88)
at org.apache.catalina.core.ApplicationFilterChain.in ternalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.do Filter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invo ke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invo keInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invo ke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke( StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:117)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invok e(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(Cont ainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(Co yoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(H ttp11Processor.java:793)
at org.apache.coyote.http11.Http11Protocol$Http11Conn ectionHandler.processConnection(Http11Protocol.jav a:702)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(P oolTcpEndpoint.java:571)
at org.apache.tomcat.util.threads.ThreadPool$ControlR unnable.run(ThreadPool.java:644)
at java.lang.Thread.run(Thread.java:595)


CLIENT:

org.springframework.remoting.RemoteAccessException : Cannot access Hessian service at [http://localhost:8080/BCM-server/ws/BCM-hessian]; nested exception is com.caucho.hessian.io.HessianProtocolException:
com.caucho.hessian.io.HessianProtocolException:
at com.caucho.hessian.client.HessianProxy.invoke(Hess ianProxy.java:171)
at $Proxy0.read(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknow n Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Un known Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.remoting.caucho.HessianClientI nterceptor.invoke(HessianClientInterceptor.java:12 0)
at org.springframework.aop.framework.ReflectiveMethod Invocation.proceed(ReflectiveMethodInvocation.java :143)
at org.springframework.aop.framework.JdkDynamicAopPro xy.invoke(JdkDynamicAopProxy.java:174)
at $Proxy1.read(Unknown Source)
at com.lh.pt.BCMgt.app.cs.main(cs.java:57)