[jira] [Commented] (KAFKA-4324) NullPointerException in StreamTask.forward

["Guozhang Wang (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KAFKA-4324?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15592588#comment-15592588 ] 

Guozhang Wang commented on KAFKA-4324:
--------------------------------------

Thanks for the report [~markshelton], could you share your topology code (of course omit any unnecessary processing logic) so I can help looking into it? Looking at {StreamTask.java:341} it seems that the {MyProcessor} do not have the right children processor to forward to, and it will be great to see the topologyBuilder code to investigate more.

> NullPointerException in StreamTask.forward
> ------------------------------------------
>
>                 Key: KAFKA-4324
>                 URL: https://issues.apache.org/jira/browse/KAFKA-4324
>             Project: Kafka
>          Issue Type: Bug
>          Components: streams
>    Affects Versions: 0.10.0.1
>            Reporter: Mark Shelton
>            Assignee: Guozhang Wang
>            Priority: Minor
>
> I have a custom processor "MyProcessor extends AbstractProcessor<String, Object>". The processor receives a message and transforms it and calls "context.forward". This sometimes results in below exception. It seems to occur when there are multiple messages available for processing.
> Stack trace:
> java.lang.NullPointerException
> 	at org.apache.kafka.streams.processor.internals.StreamTask.forward(StreamTask.java:341)
> 	at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:187)
> 	at xx.xx.xx.xx.xx.xx.xx.lambda$xx$1(xx.java:63)
> 	....
> 	at xx.xx.xx.xx.xx.process(MyProcessor.java:16)
> 	at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:68)
> 	at org.apache.kafka.streams.processor.internals.StreamTask.forward(StreamTask.java:343)
> 	at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:187)
> 	at org.apache.kafka.streams.processor.internals.SourceNode.process(SourceNode.java:64)
> 	at org.apache.kafka.streams.processor.internals.StreamTask.process(StreamTask.java:174)
> 	at org.apache.kafka.streams.processor.internals.StreamThread.runLoop(StreamThread.java:320)
> 	at org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:218)



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