SpringBoot Random ConcurrentModificationException in Spring boot Actuator

Bug report

Spring boot version: "3.2.4" Language: Kotlin Virtual threads are enabled

Description: ConcurrentModificationException happens occasionally in our backend service with no obvious reason.

Stack trace:

java.util.ConcurrentModificationException: null
    at java.base/java.util.HashMap$EntrySpliterator.tryAdvance(HashMap.java:1881)
    at java.base/java.util.stream.StreamSpliterators$WrappingSpliterator.lambda$initPartialTraversalState$0(StreamSpliterators.java:292)
    at java.base/java.util.stream.StreamSpliterators$AbstractWrappingSpliterator.fillBuffer(StreamSpliterators.java:206)
    at java.base/java.util.stream.StreamSpliterators$AbstractWrappingSpliterator.doAdvance(StreamSpliterators.java:169)
    at java.base/java.util.stream.StreamSpliterators$WrappingSpliterator.tryAdvance(StreamSpliterators.java:298)
    at java.base/java.util.Spliterators$1Adapter.hasNext(Spliterators.java:681)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getAggregateContribution(HealthEndpointSupport.java:155)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getContribution(HealthEndpointSupport.java:141)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getAggregateContribution(HealthEndpointSupport.java:156)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getContribution(HealthEndpointSupport.java:141)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getAggregateContribution(HealthEndpointSupport.java:156)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getContribution(HealthEndpointSupport.java:141)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getAggregateContribution(HealthEndpointSupport.java:156)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getContribution(HealthEndpointSupport.java:141)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getHealth(HealthEndpointSupport.java:110)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getHealth(HealthEndpointSupport.java:81)
    at org.springframework.boot.actuate.health.HealthEndpointWebExtension.health(HealthEndpointWebExtension.java:80)
    at org.springframework.boot.actuate.health.HealthEndpointWebExtension.health(HealthEndpointWebExtension.java:69)
    at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
    at java.base/java.lang.reflect.Method.invoke(Method.java:580)
    at org.springframework.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:281)
    at org.springframework.boot.actuate.endpoint.invoke.reflect.ReflectiveOperationInvoker.invoke(ReflectiveOperationInvoker.java:74)
    at org.springframework.boot.actuate.endpoint.annotation.AbstractDiscoveredOperation.invoke(AbstractDiscoveredOperation.java:60)
    at org.springframework.boot.actuate.endpoint.web.servlet.AbstractWebMvcEndpointHandlerMapping$ServletWebOperationAdapter.handle(AbstractWebMvcEndpointHandlerMapping.java:327)
    at org.springframework.boot.actuate.endpoint.web.servlet.AbstractWebMvcEndpointHandlerMapping$OperationHandler.handle(AbstractWebMvcEndpointHandlerMapping.java:434)
    at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
    at java.base/java.lang.reflect.Method.invoke(Method.java:580)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:255)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:188)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:118)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:925)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:830)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1089)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:979)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1014)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:903)
    at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:564)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:885)
    at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:205)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:110)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
    at org.springframework.web.filter.CompositeFilter$VirtualFilterChain.doFilter(CompositeFilter.java:108)
    at org.springframework.security.web.FilterChainProxy.lambda$doFilterInternal$3(FilterChainProxy.java:231)
    at org.springframework.security.web.ObservationFilterChainDecorator$FilterObservation$SimpleFilterObservation.lambda$wrap$1(ObservationFilterChainDecorator.java:479)
    at org.springframework.security.web.ObservationFilterChainDecorator$AroundFilterObservation$SimpleAroundFilterObservation.lambda$wrap$1(ObservationFilterChainDecorator.java:340)
    at org.springframework.security.web.ObservationFilterChainDecorator.lambda$wrapSecured$0(ObservationFilterChainDecorator.java:82)
    at org.springframework.security.web.ObservationFilterChainDecorator$VirtualFilterChain.doFilter(ObservationFilterChainDecorator.java:128)
    at org.springframework.security.web.access.intercept.AuthorizationFilter.doFilter(AuthorizationFilter.java:100)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.wrapFilter(ObservationFilterChainDecorator.java:240)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.doFilter(ObservationFilterChainDecorator.java:227)
    at org.springframework.security.web.ObservationFilterChainDecorator$VirtualFilterChain.doFilter(ObservationFilterChainDecorator.java:137)
    at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:126)
    at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:120)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.wrapFilter(ObservationFilterChainDecorator.java:240)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.doFilter(ObservationFilterChainDecorator.java:227)
    at org.springframework.security.web.ObservationFilterChainDecorator$VirtualFilterChain.doFilter(ObservationFilterChainDecorator.java:137)
    at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:100)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.wrapFilter(ObservationFilterChainDecorator.java:240)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.doFilter(ObservationFilterChainDecorator.java:227)
    at org.springframework.security.web.ObservationFilterChainDecorator$VirtualFilterChain.doFilter(ObservationFilterChainDecorator.java:137)
    at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:179)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.wrapFilter(ObservationFilterChainDecorator.java:240)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.doFilter(ObservationFilterChainDecorator.java:227)
    at org.springframework.security.web.ObservationFilterChainDecorator$VirtualFilterChain.doFilter(ObservationFilterChainDecorator.java:137)
    at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.wrapFilter(ObservationFilterChainDecorator.java:240)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.doFilter(ObservationFilterChainDecorator.java:227)
    at org.springframework.security.web.ObservationFilterChainDecorator$VirtualFilterChain.doFilter(ObservationFilterChainDecorator.java:137)
    at org.springframework.security.oauth2.server.resource.web.authentication.BearerTokenAuthenticationFilter.doFilterInternal(BearerTokenAuthenticationFilter.java:128)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.wrapFilter(ObservationFilterChainDecorator.java:240)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.doFilter(ObservationFilterChainDecorator.java:227)
    at org.springframework.security.web.ObservationFilterChainDecorator$VirtualFilterChain.doFilter(ObservationFilterChainDecorator.java:137)
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:107)
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:93)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.wrapFilter(ObservationFilterChainDecorator.java:240)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.doFilter(ObservationFilterChainDecorator.java:227)
    at org.springframework.security.web.ObservationFilterChainDecorator$VirtualFilterChain.doFilter(ObservationFilterChainDecorator.java:137)
    at org.springframework.security.web.csrf.CsrfFilter.doFilterInternal(CsrfFilter.java:117)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.wrapFilter(ObservationFilterChainDecorator.java:240)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.doFilter(ObservationFilterChainDecorator.java:227)
    at org.springframework.security.web.ObservationFilterChainDecorator$VirtualFilterChain.doFilter(ObservationFilterChainDecorator.java:137)
    at org.springframework.web.filter.CorsFilter.doFilterInternal(CorsFilter.java:91)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.wrapFilter(ObservationFilterChainDecorator.java:240)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.doFilter(ObservationFilterChainDecorator.java:227)
    at org.springframework.security.web.ObservationFilterChainDecorator$VirtualFilterChain.doFilter(ObservationFilterChainDecorator.java:137)
    at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:90)
    at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:75)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.wrapFilter(ObservationFilterChainDecorator.java:240)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.doFilter(ObservationFilterChainDecorator.java:227)
    at org.springframework.security.web.ObservationFilterChainDecorator$VirtualFilterChain.doFilter(ObservationFilterChainDecorator.java:137)
    at org.springframework.security.web.context.SecurityContextHolderFilter.doFilter(SecurityContextHolderFilter.java:82)
    at org.springframework.security.web.context.SecurityContextHolderFilter.doFilter(SecurityContextHolderFilter.java:69)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.wrapFilter(ObservationFilterChainDecorator.java:240)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.doFilter(ObservationFilterChainDecorator.java:227)
    at org.springframework.security.web.ObservationFilterChainDecorator$VirtualFilterChain.doFilter(ObservationFilterChainDecorator.java:137)
    at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:62)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.wrapFilter(ObservationFilterChainDecorator.java:240)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.doFilter(ObservationFilterChainDecorator.java:227)
    at org.springframework.security.web.ObservationFilterChainDecorator$VirtualFilterChain.doFilter(ObservationFilterChainDecorator.java:137)
    at org.springframework.security.web.session.DisableEncodeUrlFilter.doFilterInternal(DisableEncodeUrlFilter.java:42)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.wrapFilter(ObservationFilterChainDecorator.java:240)
    at org.springframework.security.web.ObservationFilterChainDecorator$AroundFilterObservation$SimpleAroundFilterObservation.lambda$wrap$0(ObservationFilterChainDecorator.java:323)
    at org.springframework.security.web.ObservationFilterChainDecorator$ObservationFilter.doFilter(ObservationFilterChainDecorator.java:224)
    at org.springframework.security.web.ObservationFilterChainDecorator$VirtualFilterChain.doFilter(ObservationFilterChainDecorator.java:137)
    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:233)
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:191)
    at org.springframework.web.filter.CompositeFilter$VirtualFilterChain.doFilter(CompositeFilter.java:113)
    at org.springframework.web.servlet.handler.HandlerMappingIntrospector.lambda$createCacheFilter$3(HandlerMappingIntrospector.java:195)
    at org.springframework.web.filter.CompositeFilter$VirtualFilterChain.doFilter(CompositeFilter.java:113)
    at org.springframework.web.filter.CompositeFilter.doFilter(CompositeFilter.java:74)
    at org.springframework.security.config.annotation.web.configuration.WebMvcSecurityConfiguration$CompositeFilterChainProxy.doFilter(WebMvcSecurityConfiguration.java:230)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:352)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:268)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
    at org.springframework.web.servlet.v6_0.OpenTelemetryHandlerMappingFilter.doFilter(OpenTelemetryHandlerMappingFilter.java:69)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
    at org.springframework.web.filter.ServerHttpObservationFilter.doFilterInternal(ServerHttpObservationFilter.java:109)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:167)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:482)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:115)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:735)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:344)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:391)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:896)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1744)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
    at java.base/java.lang.VirtualThread.run(VirtualThread.java:309)

Comment From: wilkinsona

There appears to be a NamedContributors implementation in your application that is not thread-safe and I would guess that a request to the health endpoint is being made on one thread while another thread is manipulating the contents of the NamedContributors instance. Unfortunately, a stack trace alone isn't enough to identify the instance. NamedContributors is an interface and we can't tell which implementation, be it one from Boot's codebase or from elsewhere, is affected. Can you please provide a minimal sample that reproduces the problem?

Comment From: spring-projects-issues

If you would like us to look at this issue, please provide the requested information. If the information is not provided within the next 7 days this issue will be closed.

Comment From: siaavush

Hey, @wilkinsona it's a good clue that it's an interface and implementation is being done by third-party starters, will dig deeper to this and give an update if I find the root cause. For now I think we can close the issue since its not a Spring Boot issue.

Comment From: siaavush

For those who are interested they can follow the topic on this issue on Spring cloud solace binder repo: https://github.com/SolaceProducts/solace-spring-cloud/issues/323