JaxWsProxyFactoryBean.create is not thread-safe
-----------------------------------------------
Key: CXF-3558
URL: https://issues.apache.org/jira/browse/CXF-3558
Project: CXF
Issue Type: Bug
Components: JAX-WS Runtime
Affects Versions: 2.4
Reporter: Tomasz Nurkiewicz
Attachments: CXF-3558.txt
While running {{JaxWsProxyFactoryBean.create}} concurrently I encountered the
following exception:
{code}Caused by: java.util.ConcurrentModificationException
at
java.util.LinkedList$ListItr.checkForComodification(LinkedList.java:761)
at java.util.LinkedList$ListItr.next(LinkedList.java:696)
at
org.apache.cxf.service.factory.AbstractServiceFactoryBean.sendEvent(AbstractServiceFactoryBean.java:71)
at
org.apache.cxf.service.factory.ReflectionServiceFactoryBean.create(ReflectionServiceFactoryBean.java:238)
at
org.apache.cxf.jaxws.support.JaxWsServiceFactoryBean.create(JaxWsServiceFactoryBean.java:202)
at
org.apache.cxf.frontend.AbstractWSDLBasedEndpointFactory.createEndpoint(AbstractWSDLBasedEndpointFactory.java:101)
at
org.apache.cxf.frontend.ClientFactoryBean.create(ClientFactoryBean.java:90)
at
org.apache.cxf.frontend.ClientProxyFactoryBean.create(ClientProxyFactoryBean.java:152)
at
org.apache.cxf.jaxws.JaxWsProxyFactoryBean.create(JaxWsProxyFactoryBean.java:142)
{code}
Although not documented (?),
{{org.apache.cxf.service.factory.ReflectionServiceFactoryBean#create}} called
somewhere during endpoint creation is {{synchronized}} which suggests whole
{{create}} is thread-safe, but apparently it's not.
I managed to discover source of this problem. I captured two threads: one
({{pool-1-thread-4}}) entered synchronized
{{ReflectionServiceFactoryBean#create}}, the second one ({{pool-1-thread-2}})
didn't made there yet but instead it calls
{{AbstractServiceFactoryBean.setBus}} outside of the {{synchronized}} block.
This causes the
{{org.apache.cxf.service.factory.AbstractServiceFactoryBean#listeners}} to be
updated, making the former thread being susceptible to
{{ConcurrentModificationException}}. Stack dumps attached.
Please either fix concurrency issue (making {{listeners}} instance of
{{java.util.concurrent.CopyOnWriteArrayList}} might not be enough though) or
document that {{JaxWsProxyFactoryBean.create}} is not thread-safe.
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