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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) -- This message was sent by Atlassian JIRA (v6.3.4#6332)