ConcurrentModificationException in MOA

[moussaoui07]

Hi,

I use MCOD for anomalies detection in stream with flink but I have an error in the code when i pass the instance to MCOD:

Caused by: java.util.ConcurrentModificationException: null
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:909)
at java.util.ArrayList$Itr.next(ArrayList.java:859)
at moa.clusterers.outliers.MCOD.MCOD.ProcessExpiredNode(MCOD.java:360)
at moa.clusterers.outliers.MCOD.MCOD.ProcessNewStreamObj(MCOD.java:398)
at moa.clusterers.outliers.MyBaseOutlierDetector.processNewInstanceImpl(MyBaseOutlierDetector.java:157)
at etl.samoa.SamoaAnomalyDetection.mapPartition(SamoaAnomalyDetection.java:84)
at org.apache.flink.runtime.operators.MapPartitionDriver.run(MapPartitionDriver.java:103)
at org.apache.flink.runtime.operators.BatchTask.run(BatchTask.java:503)
at org.apache.flink.runtime.operators.BatchTask.invoke(BatchTask.java:368)
at org.apache.flink.runtime.taskmanager.Task.run(Task.java:704)
at java.lang.Thread.run(Thread.java:748)

the line of code that causes this error is:
outlierDetector.processNewInstanceImpl(samoaInstance);

how can we avoid this error or fix it ?

Thank's in advance !

Cordially,
Anissa

[csalperwyck]

Hi, I am not sure if this can help, but you could also try to plug Flink directly to MOA: https://moa.cms.waikato.ac.nz/moa-with-apache-flink/ For testing purpose, you could also try to limit SAMOA to use only one core so that you don't have concurrent access to the "list". Best, Christophe Le mer. 27 mars 2019 à 18:10, moussaoui07 <notifications@github.com> a écrit :

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Hi, I use MCOD for anomalies detection in stream with flink but I have an error in the code when i pass the instance to MCOD: Caused by: java.util.ConcurrentModificationException: null at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:909) at java.util.ArrayList$Itr.next(ArrayList.java:859) at moa.clusterers.outliers.MCOD.MCOD.ProcessExpiredNode(MCOD.java:360) at moa.clusterers.outliers.MCOD.MCOD.ProcessNewStreamObj(MCOD.java:398) at moa.clusterers.outliers.MyBaseOutlierDetector.processNewInstanceImpl(MyBaseOutlierDetector.java:157) at etl.samoa.SamoaAnomalyDetection.mapPartition(SamoaAnomalyDetection.java:84) at org.apache.flink.runtime.operators.MapPartitionDriver.run(MapPartitionDriver.java:103) at org.apache.flink.runtime.operators.BatchTask.run(BatchTask.java:503) at org.apache.flink.runtime.operators.BatchTask.invoke(BatchTask.java:368) at org.apache.flink.runtime.taskmanager.Task.run(Task.java:704) at java.lang.Thread.run(Thread.java:748) the line of code that causes this error is: outlierDetector.processNewInstanceImpl(samoaInstance); how can we avoid this error or fix it ? Thank's in advance ! Cordially, Anissa — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#170>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AKC21-p3_VRhdMgUs1izuaqpLqkZZVV5ks5va6X-gaJpZM4cOVhC> .

[moussaoui07]

Hello,

Thank you for your reply !

I have already tried to put a single heart with a flink setParallelism at 1 but I always have the competition error !!

So I do not know how to correct this error.

Best,
Aniisa

[csalperwyck]

Hello, I think it's a bug in their code... There a proposal to fix it there but you need to modify the source code: https://groups.google.com/forum/#!topic/moa-users/QhvNcpIRIFg Best, Christophe Le sam. 6 avr. 2019 à 10:59, moussaoui07 <notifications@github.com> a écrit :

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Hello, Thank you for your reply ! I have already tried to put a single heart with a flink setParallelism at 1 but I always have the competition error !! So I do not know how to correct this error. Best, Aniisa — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#170 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AKC21x2bExNWIgOnogEb1Q0ly0GrV5_0ks5veGIPgaJpZM4cOVhC> .