我的for循环得到一个ConcurrentModificationException，我不知道如何解决这个问题。
这是我的代码：
for(Map.Entry<String,ControlFieldVO> entry:oldPresentationMap.entrySet()) {
if(!keyValue.contains(entry.getKey())) {
oldPresentationMap.remove(entry.getKey());
}
在第一行获取concurrentModification异常请帮助以下是堆栈跟踪：
<<<[2014/05/24 17:29:03.595]:WebContainer : 10:1400932743595:java.lang.String: DEBUG:c7WtHlNAp7cfpveDNFSG8Iq:isParameterNotNull::Paremeter :nullControlFieldVO :com.td.mbnasales.core.jackrabbit.vo.PresentationImageVO@5f415f41[sameParentImgName=<null>,imgName=<null>,value=,isParentValueOverwritten=false,isErrorInValue=<null>,isValueDiffFromPublishedVersion=false,sameParentValue=,publishedValue=<null>,isMultiEditFieldValueDiff=false,isChanged=<null>] >>>
<<<[2014/05/24 17:29:03.595]:WebContainer : 10:1400932743595:java.lang.String: DEBUG:c7WtHlNAp7cfpveDNFSG8Iq:isParameterNotNull::Paremeter :nullControlFieldVO :com.td.mbnasales.core.jackrabbit.vo.PresentationImageVO@5f205f20[sameParentImgName=<null>,imgName=<null>,value=<null>,isParentValueOverwritten=false,isErrorInValue=<null>,isValueDiffFromPublishedVersion=false,sameParentValue=<null>,publishedValue=<null>,isMultiEditFieldValueDiff=<null>,isChanged=<null>] >>>
<<<[2014/05/24 17:29:03.600]:WebContainer : 10:1400932743600:java.lang.String: ERROR:c7WtHlNAp7cfpveDNFSG8Iq:resolveException::Exception Occured:java.util.ConcurrentModificationException >>>
<<<[2014/05/24 17:29:03.603]:WebContainer : 10:1400932743603:java.lang.String: ERROR:c7WtHlNAp7cfpveDNFSG8Iq:resolveException::Stack Trace :java.util.ConcurrentModificationException
at java.util.LinkedHashMap$AbstractMapIterator.checkConcurrentMod(Unknown Source)
at java.util.LinkedHashMap$AbstractMapIterator.makeNext(Unknown Source)
at java.util.LinkedHashMap$EntryIterator.next(Unknown Source)
at java.util.LinkedHashMap$EntryIterator.next(Unknown Source)
at com.td.mbnasales.wwwcms.controller.helper.EntityHelper.mergePresentationSessionMultiEntityVO(EntityHelper.java:5849)
at com.td.mbnasales.wwwcms.controller.helper.EntityHelper.multiUpdateSessionEntityVO(EntityHelper.java:6010)
at com.td.mbnasales.wwwcms.controller.EntityController.multiUpdateSessionEntityVO(EntityController.java:5999)
at sun.reflect.GeneratedMethodAccessor9348.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37)
at java.lang.reflect.Method.invoke(Method.java:599)
at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:213)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:738)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:831)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1657)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1597)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:131)
at com.td.mbnasales.wwwcms.filters.AccessControlFilter.doFilter(AccessControlFilter.java:77)
at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:188)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:116)
at com.td.mbnasales.wwwcms.filters.BreadCrumbFilter.doFilter(BreadCrumbFilter.java:336)
at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:188)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:116)
at com.td.mbnasales.wwwcms.filters.LocaleFilter.doFilterInternal(LocaleFilter.java:110)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:188)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:116)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:188)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:116)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:322)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:182)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.session.ConcurrentSessionFilter.doFilter(ConcurrentSessionFilter.java:125)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:184)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:155)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:188)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:116)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain._doFilter(WebAppFilterChain.java:77)
at com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:908)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:934)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:502)
at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.handleRequest(ServletWrapperImpl.java:181)
at com.ibm.ws.webcontainer.servlet.CacheServletWrapper.handleRequest(CacheServletWrapper.java:91)
at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:864)
at com.ibm.ws.webcontainer.WSWebContainer.handleRequest(WSWebContainer.java:1592)
at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:186)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:452)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewRequest(HttpInboundLink.java:511)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.processRequest(HttpInboundLink.java:305)
at com.ibm.ws.http.channel.inbound.impl.HttpICLReadCallback.complete(HttpICLReadCallback.java:83)
at com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(AioReadCompletionListener.java:165)
at com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyncFuture.java:217)
at com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(AsyncChannelFuture.java:161)
at com.ibm.io.async.AsyncFuture.completed(AsyncFuture.java:138)
at com.ibm.io.async.ResultHandler.complete(ResultHandler.java:204)
at com.ibm.io.async.ResultHandler.runEventProcessingLoop(ResultHandler.java:775)
at com.ibm.io.async.ResultHandler$2.run(ResultHandler.java:905)
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1613)
>>>
<<<[2014/05/24 17:29:25.392]:WebContainer : 10:1400932765392:java.lang.String: DEBUG:c7WtHlNAp7cfpveDNFSG8Iq:validateLocalParam -->::called >>>
<<<[2014/05/24 17:29:25.393]:WebContainer : 10:1400932765393:com.td.mbnasales.core.helper.BreadCrumbHelper: DEBUG:c7WtHlNAp7cfpveDNFSG8Iq:getBreadCrumbDetails::---- Enter --- >>>
<<<[2014/05/24 17:29:25.393]:WebContainer : 10:1400932765393:com.td.mbnasales.core.helper.BreadCrumbHelper: DEBUG:c7WtHlNAp7cfpveDNFSG8Iq:getBreadCrumbDetails:: --- Exit --- >>>
<<<[2014/05/24 17:29:25.485]:WebContainer : 10:1400932765485:com.td.mbnasales.core.service.impl.MarketingZoneServiceImpl: DEBUG:c7WtHlNAp7cfpveDNFSG8Iq:getContent::---- Enter --- >>>
<<<[2014/05/24 17:29:25.485]:WebContainer : 10:1400932765485:com.td.mbnasales.core.jcr.manager.impl.JackRabbitManagerImpl: DEBUG:c7WtHlNAp7cfpveDNFSG8Iq:get::---- Enter --- >>>
<<<[2014/05/24 17:29:25.485]:WebContainer : 10:1400932765485:java.lang.String: DEBUG:c7WtHlNAp7cfpveDNFSG8Iq:New JackRabbit Session created for the user::JackRabbitManagerImpl >>>
<<<[2014/05/24 17:29:25.486]:WebContainer : 10:1400932765486:com.td.mbnasales.core.jcr.manager.impl.JackRabbitManagerImpl: PERF:c7WtHlNAp7cfpveDNFSG8Iq::TIME:<TIMESTAMP> (0) 2014/05/24 17:29:25:485 to 17:29:25:486 1 ms Taken for getOCMnullnull
>>>
<<<[2014/05/24 17:29:25.744]:WebContainer : 10:1400932765744:com.td.mbnasales.core.jcr.manager.impl.JackRabbitManagerImpl: PERF:c7WtHlNAp7cfpveDNFSG8Iq:CECOM:TIME:<TIMESTAMP> (0) 2014/05/24 17:29:25:485 to 17:29:25:743 258 ms Taken for get(ContentItem contentItem,ContentItemAttribute contentItemAttribute)null - CECOM
>>>
<<<[2014/05/24 17:29:25.744]:WebContainer : 10:1400932765744:com.td.mbnasales.core.jcr.manager.impl.JackRabbitManagerImpl: DEBUG:c7WtHlNAp7cfpveDNFSG8Iq:get:: --- Exit --- >>>
<<<[2014/05/24 17:29:25.745]:WebContainer : 10:1400932765745:com.td.mbnasales.core.jcr.manager.impl.JackRabbitManagerImpl: DEBUG:c7WtHlNAp7cfpveDNFSG8Iq:getPublishedVersion::---- Enter --- >>>
<<<[2014/05/24 17:29:25.745]:WebContainer : 10:1400932765745:java.lang.String: DEBUG:c7WtHlNAp7cfpveDNFSG8Iq:New JackRabbit Session created for the user::JackRabbitManagerImpl >>>
<<<[2014/05/24 17:29:25.745]:WebContainer : 10:1400932765745:com.td.mbnasales.core.jcr.manager.impl.JackRabbitManagerImpl: PERF:c7WtHlNAp7cfpveDNFSG8Iq::TIME:<TIMESTAMP> (0) 2014/05/24 17:29:25:745 to 17:29:25:745 0 ms Taken for getOCMnullnull
>>>
<<<[2014/05/24 17:29:25.948]:WebContainer : 10:1400932765948:java.lang.String: DEBUG:c7WtHlNAp7cfpveDNFSG8Iq:New JackRabbit Session created for the user::JackRabbitManagerImpl >>>
<<<[2014/05/24 17:29:25.949]:WebContainer : 10:1400932765949:com.td.mbnasales.core.jcr.manager.impl.JackRabbitManagerImpl: PERF:c7WtHlNAp7cfpveDNFSG8Iq::TIME:<TIMESTAMP> (0) 2014/05/24 1
任何人都可以帮助我吗？
答案 0 :(得分：2)
如果您尝试在迭代时修改地图，则会获得ConcurrentModificationException。你可以通过以下方式解决这个问题：
答案 1 :(得分：0)
您已在地图的键集上获得了一个迭代器，并在结构上直接修改了地图。此类操作的行为由map实现定义。如果你看一下hash map的javadoc：
所有这类＆＃34;集合视图返回的迭代器 方法＆＃34;快速失败：如果地图在任何地方进行了结构修改 创建迭代器之后的时间，除了通过之外的任何方式 迭代器自己的remove方法，迭代器会抛出一个 ConcurrentModificationException的。因此，面对并发 修改，迭代器快速而干净地失败，而不是 在不确定的时间冒着任意的，非确定性的行为 在将来。
它描述了您所看到的行为。
不要使用for：next语法，而是使用Iterator的旧方法并调用Iterator.remove删除项目。