Thanks Lloyd, for the quick response.
I'll file a bug.
Thanks
Jothir
Lloyd L Chambers wrote:
> Jothir,
>
> Please file a bug.
>
> The exception indicates that an MBean has already been registered,
> which suggests a possible race condition with multiple threads or a
> logic error that tries to register twice.
>
> In examining CascadingLifecycleImpl, I note that it is definitely not
> thread safe, nor is InstanceCascadingMBean, which calls it. In
> particular:
>
> - 'cMap' is not synchronized in any way; it is not a synchronized map
> (eg Collections.synchronizedMap).
> - cascadeInstance() first removes an entry ('cascadingAgentName'),
> then later adds its again. The method is not synchronized, and even
> if 'cMap' were synchronized, the method would still need to use a
> locking strategy.
>
> Lloyd Chambers
>
>
> On Dec 20, 2006, at 10:30 PM, jothir ganesan wrote:
>
>> Hi All,
>>
>> I am in appserver SQE team and I executed a list of tests using AS
>> 9.1 EE build 28. Most of my tests restart an instance in a cluster
>> (because we test for failover and highavailability features of
>> appserver). In the course of execution, when the instance was
>> restarted by one test, I noticed "InstanceAlreadyExistsException"
>> exception in DAS's server.log. After that, the instance didnot get
>> started completely. The stack trace is attached below.
>>
>>
>> [#|2006-12-15T02:59:59.636+0530|WARNING|sun-appserver-ee9.1|
>> javax.enterprise.system.stream.err|_ThreadID=1617;_ThreadName=RMI
>> TCP Connection
>> (5731)-10.12.163.195;_RequestID=3b3998ba-5df5-464b-8a54-c842326f3532;|
>> javax.management.InstanceAlreadyExistsException:
>> com.sun.appserv:type=CascadingAgent,serverName=instance1
>> at com.sun.jmx.mbeanserver.RepositorySupport.addMBean
>> (RepositorySupport.java:452)
>> at
>> com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.internal_addObje
>> ct(DefaultMBeanServerInterceptor.java:1410)
>> at
>> com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerObject
>> (DefaultMBeanServerInterceptor.java:936)
>> at
>> com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean
>> (DefaultMBeanServerInterceptor.java:337)
>> at com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean
>> (JmxMBeanServer.java:497)
>> at sun.reflect.GeneratedMethodAccessor10.invoke(Unknown Source)
>> at sun.reflect.DelegatingMethodAccessorImpl.invoke
>> (DelegatingMethodAccessorImpl.java:25)
>> at java.lang.reflect.Method.invoke(Method.java:585)
>> at com.sun.enterprise.admin.util.proxy.ProxyClass.invoke
>> (ProxyClass.java:77)
>> at $Proxy1.registerMBean(Unknown Source)
>> at
>> com.sun.enterprise.admin.server.core.jmx.SunoneInterceptor.registerMBe
>> an(SunoneInterceptor.java:268)
>> at
>> com.sun.enterprise.ee.admin.cascading.CascadingLifecycleImpl.cascadeIn
>> stance(CascadingLifecycleImpl.java:380)
>> at
>> com.sun.enterprise.ee.admin.cascading.InstanceCascadingMBean.cascadeIn
>> stance(InstanceCascadingMBean.java:302)
>> at
>> com.sun.enterprise.ee.admin.cascading.InstanceCascadingMBean.invoke
>> (InstanceCascadingMBean.java:216)
>> at com.sun.jmx.mbeanserver.DynamicMetaDataImpl.invoke
>> (DynamicMetaDataImpl.java:213)
>> at com.sun.jmx.mbeanserver.MetaDataImpl.invoke
>> (MetaDataImpl.java:220)
>> at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke
>> (DefaultMBeanServerInterceptor.java:815)
>> at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke
>> (JmxMBeanServer.java:784)
>> at sun.reflect.GeneratedMethodAccessor21.invoke(Unknown Source)
>> at sun.reflect.DelegatingMethodAccessorImpl.invoke
>> (DelegatingMethodAccessorImpl.java:25)
>> at java.lang.reflect.Method.invoke(Method.java:585)
>> at com.sun.enterprise.admin.util.proxy.ProxyClass.invoke
>> (ProxyClass.java:77)
>> at $Proxy1.invoke(Unknown Source)
>> at
>> com.sun.enterprise.admin.server.core.jmx.SunoneInterceptor.invoke
>> (SunoneInterceptor.java:297)
>> at javax.management.remote.rmi.RMIConnectionImpl.doOperation
>> (RMIConnectionImpl.java:1408)
>> at javax.management.remote.rmi.RMIConnectionImpl.access$100
>> (RMIConnectionImpl.java:81)
>> at javax.management.remote.rmi.RMIConnectionImpl
>> $PrivilegedOperation.run(RMIConnectionImpl.java:1245)
>> at
>> javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation
>> (RMIConnectionImpl.java:1341)
>> at javax.management.remote.rmi.RMIConnectionImpl.invoke
>> (RMIConnectionImpl.java:782)
>> at sun.reflect.GeneratedMethodAccessor130.invoke(Unknown Source)
>> at sun.reflect.DelegatingMethodAccessorImpl.invoke
>> (DelegatingMethodAccessorImpl.java:25)
>> at java.lang.reflect.Method.invoke(Method.java:585)
>> at sun.rmi.server.UnicastServerRef.dispatch
>> (UnicastServerRef.java:294)
>> at sun.rmi.transport.Transport$1.run(Transport.java:153)
>> at java.security.AccessController.doPrivileged(Native Method)
>> at sun.rmi.transport.Transport.serviceCall(Transport.java:149)
>> at sun.rmi.transport.tcp.TCPTransport.handleMessages
>> (TCPTransport.java:466)
>> at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run
>> (TCPTransport.java:707)
>> at java.lang.Thread.run(Thread.java:595)
>> |#]
>>
>> Could anyone please let me know the cause of this issue?
>>
>> Thanks
>> Jothir
>>
>
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