[CXF-7784] java.util.ConcurrentModificationException on WebTarget.request()

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Information Provided
• Affects Version/s: 3.1.14
• Component/s: JAX-RS
• Labels: cxf-rt-frontend-jaxrs

Environment

• Hystrix 1.5.9
• Spring-Boot 1.5.14
• JAXRS 3.1.14

• Estimated Complexity: Unknown
• Assignee: Andriy Redko
• Reporter: Dominic Schmoigl
• Created: 07/Jul/18 22:32
• Updated: 23/Jul/18 10:38
• Resolved: 22/Jul/18 22:57

Description

By chance we stumbled over a case, where calling

webTarget.request()

sometimes may lead to a java.util.ConcurrentModificationException, if the webTarget is created in one thread, but the call to .request() is performed in multiple concurrent threads afterwards. In our environment it was possible to provoke the exception with probability of ~10%, if run with 4 threads in parallel.

The callstack, which we could isolate, was:

Caused by: java.util.ConcurrentModificationException
 at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:909)
 at java.util.ArrayList$Itr.next(ArrayList.java:859)
 at org.apache.cxf.jaxrs.provider.ProviderFactory.injectContextProxies(ProviderFactory.java:638)
 at org.apache.cxf.jaxrs.provider.ProviderFactory.setCommonProviders(ProviderFactory.java:600)
 at org.apache.cxf.jaxrs.client.ClientProviderFactory.setProviders(ClientProviderFactory.java:74)
 at org.apache.cxf.jaxrs.provider.ProviderFactory.setUserProviders(ProviderFactory.java:791)
 at org.apache.cxf.jaxrs.client.spec.ClientImpl$WebTargetImpl.request(ClientImpl.java:282)
 at <<custom-coding-which-calls-webTarget.request()>>

We currently have a workaround with

synchronized (webTarget) {
   webTarget.request();
}

which isn't perfect, but good enough for our case.

 

Is this case known to you? We did not try to reproduce the issue in isolation, yet (as it was hard enough to find it in our application already). If we should give it a try, please notify us.