I have a business process with 5 manual activities with a fork, initially all user tasks are assigned to business admin
My scenario is like start process instance for this Process, then business admin deligate each task to a seperate user and that user will complete the task then next task will be created
When i execute this scenario with 100 concurrent users in load runner then 2% of the markdone operations are failing with Concurrent modifcation exception
[java] java.util.ConcurrentModificationException
[java] at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
[java] at java.util.AbstractList$Itr.next(AbstractList.java:343)
[java] at org.jbpm.task.event.MessagingTaskEventListener.taskCompleted(MessagingTaskEventListener.java:72)
[java] at org.jbpm.task.event.TaskEventSupport.fireTaskCompleted(TaskEventSupport.java:47)
[java] at org.jbpm.task.service.TaskServiceSession.postTaskCompleteOperation(TaskServiceSession.java:497)
[java] at org.jbpm.task.service.TaskServiceSession.taskOperation(TaskServiceSession.java:463)
[java] at org.jbpm.task.service.TaskServerHandler.messageReceived(TaskServerHandler.java:84)
[java] at org.jbpm.task.service.mina.MinaTaskServerHandler.messageReceived(MinaTaskServerHandler.java:41)
[java] at org.apache.mina.core.filterchain.DefaultIoFilterChain$TailFilter.messageReceived(DefaultIoFilterChain.java:716)
[java] at org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:434)
[java] at org.apache.mina.core.filterchain.DefaultIoFilterChain.access$1200(DefaultIoFilterChain.java:46)
[java] at org.apache.mina.core.filterchain.DefaultIoFilterChain$EntryImpl$1.messageReceived(DefaultIoFilterChain.java:796)
[java] at org.apache.mina.filter.codec.ProtocolCodecFilter$ProtocolDecoderOutputImpl.flush(ProtocolCodecFilter.java:427)
[java] at org.apache.mina.filter.codec.ProtocolCodecFilter.messageReceived(ProtocolCodecFilter.java:245)
[java] at org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:434)
[java] at org.apache.mina.core.filterchain.DefaultIoFilterChain.access$1200(DefaultIoFilterChain.java:46)
[java] at org.apache.mina.core.filterchain.DefaultIoFilterChain$EntryImpl$1.messageReceived(DefaultIoFilterChain.java:796)
[java] at org.apache.mina.filter.logging.LoggingFilter.messageReceived(LoggingFilter.java:177)
[java] at org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:434)
[java] at org.apache.mina.core.filterchain.DefaultIoFilterChain.access$1200(DefaultIoFilterChain.java:46)
[java] at org.apache.mina.core.filterchain.DefaultIoFilterChain$EntryImpl$1.messageReceived(DefaultIoFilterChain.java:796)
[java] at org.apache.mina.core.filterchain.IoFilterAdapter.messageReceived(IoFilterAdapter.java:119)
[java] at org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:434)
[java] at org.apache.mina.core.filterchain.DefaultIoFilterChain.fireMessageReceived(DefaultIoFilterChain.java:426)
[java] at org.apache.mina.core.polling.AbstractPollingIoProcessor.read(AbstractPollingIoProcessor.java:692)
[java] at org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:645)
[java] at org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:634)
[java] at org.apache.mina.core.polling.AbstractPollingIoProcessor.access$400(AbstractPollingIoProcessor.java:66)
[java] at org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.run(AbstractPollingIoProcessor.java:1078)
[java] at org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:64)
[java] at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
[java] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
[java] at java.lang.Thread.run(Thread.java:662)