I've just seen that (rare) exception in an otherwise well-behaving web applicaiton of ours.

It would be great to hear whether that's a known issue and which release contains a fix. I see a couple of similar issued but with different call stacks. So may be this is a new variant?

Thank you!

Feb 20, 2020 7:38:17 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [springmvc] in context with path [] threw exception [Request processing failed; nested exception is java.util.ConcurrentModificationException] with root cause
java.util.ConcurrentModificationException
    at java.base/java.util.HashMap.computeIfAbsent(HashMap.java:1134)
    at org.springframework.util.LinkedMultiValueMap.add(LinkedMultiValueMap.java:89)
    at org.springframework.web.accept.MappingMediaTypeFileExtensionResolver.addMapping(MappingMediaTypeFileExtensionResolver.java:80)
    at org.springframework.web.accept.AbstractMappingContentNegotiationStrategy.resolveMediaTypeKey(AbstractMappingContentNegotiationStrategy.java:121)
    at org.springframework.web.accept.AbstractMappingContentNegotiationStrategy.resolveMediaTypes(AbstractMappingContentNegotiationStrategy.java:102)
    at org.springframework.web.accept.ContentNegotiationManager.resolveMediaTypes(ContentNegotiationManager.java:124)
    at org.springframework.web.servlet.mvc.condition.ProducesRequestCondition.getAcceptedMediaTypes(ProducesRequestCondition.java:257)
    at org.springframework.web.servlet.mvc.condition.ProducesRequestCondition.getMatchingCondition(ProducesRequestCondition.java:194)
    at org.springframework.web.servlet.mvc.method.RequestMappingInfo.getMatchingCondition(RequestMappingInfo.java:235)
    at org.springframework.web.servlet.mvc.method.RequestMappingInfoHandlerMapping.getMatchingMapping(RequestMappingInfoHandlerMapping.java:93)
    at org.springframework.web.servlet.mvc.method.RequestMappingInfoHandlerMapping.getMatchingMapping(RequestMappingInfoHandlerMapping.java:57)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.addMatchingMappings(AbstractHandlerMethodMapping.java:425)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.lookupHandlerMethod(AbstractHandlerMethodMapping.java:391)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.getHandlerInternal(AbstractHandlerMethodMapping.java:365)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.getHandlerInternal(AbstractHandlerMethodMapping.java:65)
    at org.springframework.web.servlet.handler.AbstractHandlerMapping.getHandler(AbstractHandlerMapping.java:401)
    at org.springframework.web.servlet.DispatcherServlet.getHandler(DispatcherServlet.java:1231)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1014)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:897)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.sitemesh.webapp.contentfilter.ContentBufferingFilter.bufferAndPostProcess(ContentBufferingFilter.java:169)
    at org.sitemesh.webapp.contentfilter.ContentBufferingFilter.doFilter(ContentBufferingFilter.java:126)
    at org.sitemesh.config.ConfigurableSiteMeshFilter.doFilter(ConfigurableSiteMeshFilter.java:163)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.multipart.support.MultipartFilter.doFilterInternal(MultipartFilter.java:124)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:209)
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:357)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:270)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at de.hybris.platform.servicelayer.web.AbstractPlatformFilterChain$InternalFilterChain.doFilter(AbstractPlatformFilterChain.java:329)
    at de.hybris.platform.servicelayer.web.AbstractPlatformFilterChain.processStandardFilterChain(AbstractPlatformFilterChain.java:207)
    at de.hybris.platform.servicelayer.web.AbstractPlatformFilterChain.doFilterInternal(AbstractPlatformFilterChain.java:184)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:357)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:270)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at de.hybris.platform.servicelayer.web.XSSFilter.processPatternsAndDoFilter(XSSFilter.java:358)
    at de.hybris.platform.servicelayer.web.XSSFilter.doFilter(XSSFilter.java:306)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:543)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:609)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:810)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1623)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.base/java.lang.Thread.run(Thread.java:834)

Comment From: jhoeller

This looks like a duplicate of #23064, fixed in 5.1.8 and higher.