[Resteasy-users] Intermittent java.util.ConcurrentModificationException due to jboss.resteasy.core.ServerResponseWriter

[Danilo C. M. <dco...@gm...>]

Hello everyone,

I have been facing an intermittent issue with RESTEasy 3.0.10 from WildFly
8.2 and I don't know how to interpret it. Once a day, I usually see the
following kind of log entry from WildFly/RESTEasy:

16:11:46,385 ERROR [io.undertow.request] (default task-58) UT005023:
Exception handling request to /project/rest/entity/query:
org.jboss.resteasy.spi.UnhandledException:
java.util.ConcurrentModificationException

       at
org.jboss.resteasy.core.ExceptionHandler.handleException(ExceptionHandler.java:247)
[resteasy-jaxrs-3.0.10.Final.jar:]

       at
org.jboss.resteasy.core.SynchronousDispatcher.writeException(SynchronousDispatcher.java:149)
[resteasy-jaxrs-3.0.10.Final.jar:]

       at
org.jboss.resteasy.core.SynchronousDispatcher.writeResponse(SynchronousDispatcher.java:432)
[resteasy-jaxrs-3.0.10.Final.jar:]

       at
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:376)
[resteasy-jaxrs-3.0.10.Final.jar:]

       at
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:179)
[resteasy-jaxrs-3.0.10.Final.jar:]

       at
org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:220)
[resteasy-jaxrs-3.0.10.Final.jar:]

       at
org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:56)
[resteasy-jaxrs-3.0.10.Final.jar:]

       at
org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:51)
[resteasy-jaxrs-3.0.10.Final.jar:]

       at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
[jboss-servlet-api_3.1_spec-1.0.0.Final.jar:1.0.0.Final]

       at
io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
[undertow-servlet-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:61)
[undertow-servlet-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
[undertow-servlet-1.1.0.Final.jar:1.1.0.Final]

       at
org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)

       at
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
[undertow-core-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
[undertow-servlet-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:56)
[undertow-servlet-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
[undertow-core-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:45)
[undertow-core-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:63)
[undertow-servlet-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:58)
[undertow-core-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:70)
[undertow-servlet-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.security.handlers.SecurityInitialHandler.handleRequest(SecurityInitialHandler.java:76)
[undertow-core-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
[undertow-core-1.1.0.Final.jar:1.1.0.Final]

       at
org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)

       at
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
[undertow-core-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
[undertow-core-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:261)
[undertow-servlet-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:247)
[undertow-servlet-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:76)
[undertow-servlet-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:166)
[undertow-servlet-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.server.Connectors.executeRootHandler(Connectors.java:197)
[undertow-core-1.1.0.Final.jar:1.1.0.Final]

       at
io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:759)
[undertow-core-1.1.0.Final.jar:1.1.0.Final]

       at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
[rt.jar:1.8.0_31]

       at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
[rt.jar:1.8.0_31]

       at java.lang.Thread.run(Thread.java:745) [rt.jar:1.8.0_31]

Caused by: java.util.ConcurrentModificationException

       at java.util.ArrayList$Itr.remove(ArrayList.java:873)
[rt.jar:1.8.0_31]

       at
org.jboss.resteasy.core.ServerResponseWriter.commitHeaders(ServerResponseWriter.java:225)
[resteasy-jaxrs-3.0.10.Final.jar:]

       at
org.jboss.resteasy.core.ServerResponseWriter.writeNomapResponse(ServerResponseWriter.java:54)
[resteasy-jaxrs-3.0.10.Final.jar:]

       at
org.jboss.resteasy.core.SynchronousDispatcher.writeResponse(SynchronousDispatcher.java:427)
[resteasy-jaxrs-3.0.10.Final.jar:]

       ... 32 more

This seems to happen to "random" endpoints from the API, and I don't know
what the cause might be. I have a JAX-RS filter that sets a cookie in most
responses from the API, but I can't identify any problems with it.

Please, does anyone have any ideas?

Thank you in advance for any help.

Respectfully yours,

Danilo Cominotti Marques