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Aljoscha Krettek commented on FLINK-5551: ----------------------------------------- I think this can happen when canceling happens before the Task/Operator is properly set up? The exception is a follow-up exceptions that happens because of the canceling. Do we need to address this, [~StephanEwen]? > NPE at SourceStreamTask > ----------------------- > > Key: FLINK-5551 > URL: https://issues.apache.org/jira/browse/FLINK-5551 > Project: Flink > Issue Type: Bug > Components: DataStream API > Affects Versions: 1.2.0 > Reporter: Andrey > > Prerequisites: > * Configure hdfs-based backend for the job > * cancel it using webapp admin > In logs during job cancel: > {code} > 2017-01-17 16:22:08,756 INFO > org.apache.flink.streaming.runtime.tasks.StreamTask - Using > user-defined state backend: File State Backend @ > hdfs://host:port/flink-checkpoints > 2017-01-17 16:22:08,756 INFO org.apache.flink.runtime.taskmanager.Task > - Attempting to cancel task Source: Custom Source -> Filter > (3/8) > 2017-01-17 16:22:08,756 INFO org.apache.flink.runtime.taskmanager.Task > - Source: Custom Source -> Filter (3/8) switched to CANCELING > 2017-01-17 16:22:08,756 INFO org.apache.flink.runtime.taskmanager.Task > - Triggering cancellation of task code Source: Custom Source -> > Filter (3/8) (559a224c8ef78884db727dab0b2d5e99). > 2017-01-17 16:22:08,756 ERROR org.apache.flink.runtime.taskmanager.Task > - Error while canceling the task > java.lang.NullPointerException > at > org.apache.flink.streaming.runtime.tasks.SourceStreamTask.cancelTask(SourceStreamTask.java:61) > at > org.apache.flink.streaming.runtime.tasks.StreamTask.cancel(StreamTask.java:349) > at > org.apache.flink.runtime.taskmanager.Task$TaskCanceler.run(Task.java:1214) > at java.lang.Thread.run(Thread.java:745) > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)