menuitem upload="true" error

<button id="uploadBtn" label="fileUpload" upload="true"></button>

public void onUpload$uploadBtn(UploadEvent event)

<menuitem id="uploadFile" label="fileUpload" upload="true"/>

>>java.lang.IllegalArgumentException: argument type mismatch
>>	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.zkoss.zk.ui.impl.EventProcessor.process0(EventProcessor.java:207)
>>	at org.zkoss.zk.ui.impl.EventProcessor.process(EventProcessor.java:138)
>>	at org.zkoss.zk.ui.event.Events.sendEvent(Events.java:306)
>>	at org.zkoss.zk.ui.event.Events.sendEvent(Events.java:329)
>>	at org.zkoss.zk.ui.AbstractComponent$ForwardListener.onEvent(AbstractComponent.java:3034)
>>	at org.zkoss.zk.ui.impl.EventProcessor.process0(EventProcessor.java:192)
>>	at org.zkoss.zk.ui.impl.EventProcessor.process(EventProcessor.java:138)
>>	at org.zkoss.zk.ui.impl.UiEngineImpl.processEvent(UiEngineImpl.java:1636)
>>	at org.zkoss.zk.ui.impl.UiEngineImpl.process(UiEngineImpl.java:1420)
>>	at org.zkoss.zk.ui.impl.UiEngineImpl.execUpdate(UiEngineImpl.java:1133)
>>	at org.zkoss.zk.au.http.DHtmlUpdateServlet.process(DHtmlUpdateServlet.java:567)
>>	at org.zkoss.zk.au.http.DHtmlUpdateServlet.doGet(DHtmlUpdateServlet.java:462)
>>	at org.zkoss.zk.au.http.DHtmlUpdateServlet.doPost(DHtmlUpdateServlet.java:470)
>>	at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
>>	at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
>>	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
>>	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
>>	at org.jwebap.plugin.tracer.http.DetectFilter.doFilter(DetectFilter.java:95)
>>	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
>>	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
>>	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:96)
>>	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
>>	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
>>	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
>>	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
>>	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
>>	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
>>	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
>>	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:555)
>>	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
>>	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
>>	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857)
>>	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
>>	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
>>	at java.lang.Thread.run(Thread.java:662)