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Posted to issues@flink.apache.org by "Flink Jira Bot (Jira)" <ji...@apache.org> on 2022/01/07 10:41:00 UTC

[jira] [Updated] (FLINK-5319) ClassCastException when reusing an inherited method reference as KeySelector for different classes

     [ https://issues.apache.org/jira/browse/FLINK-5319?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Flink Jira Bot updated FLINK-5319:
----------------------------------
      Labels: auto-deprioritized-major auto-deprioritized-minor auto-unassigned  (was: auto-deprioritized-major auto-unassigned stale-minor)
    Priority: Not a Priority  (was: Minor)

This issue was labeled "stale-minor" 7 days ago and has not received any updates so it is being deprioritized. If this ticket is actually Minor, please raise the priority and ask a committer to assign you the issue or revive the public discussion.


> ClassCastException when reusing an inherited method reference as KeySelector for different classes
> --------------------------------------------------------------------------------------------------
>
>                 Key: FLINK-5319
>                 URL: https://issues.apache.org/jira/browse/FLINK-5319
>             Project: Flink
>          Issue Type: Bug
>          Components: API / DataStream
>    Affects Versions: 1.2.0
>            Reporter: Alexander Chermenin
>            Priority: Not a Priority
>              Labels: auto-deprioritized-major, auto-deprioritized-minor, auto-unassigned
>
> Code sample:
> {code}static abstract class A {
>     int id;
>     A(int id) {this.id = id; }
>     int getId() { return id; }
> }
> static class B extends A { B(int id) { super(id % 3); } }
> static class C extends A { C(int id) { super(id % 2); } }
> private static B b(int id) { return new B(id); }
> private static C c(int id) { return new C(id); }
> /**
>  * Main method.
>  */
> public static void main(String[] args) throws Exception {
>     StreamExecutionEnvironment environment =
>         StreamExecutionEnvironment.getExecutionEnvironment();
>     B[] bs = IntStream.range(0, 10).mapToObj(Test::b).toArray(B[]::new);
>     C[] cs = IntStream.range(0, 10).mapToObj(Test::c).toArray(C[]::new);
>     DataStreamSource<B> bStream = environment.fromElements(bs);
>     DataStreamSource<C> cStream = environment.fromElements(cs);
>     bStream.keyBy((KeySelector<B, Integer>) A::getId).print();
>     cStream.keyBy((KeySelector<C, Integer>) A::getId).print();
>     environment.execute();
> }
> {code}
> This code throws next exception:
> {code}Exception in thread "main" org.apache.flink.runtime.client.JobExecutionException: Job execution failed.
> 	at org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$7.apply$mcV$sp(JobManager.scala:901)
> 	at org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$7.apply(JobManager.scala:844)
> 	at org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$7.apply(JobManager.scala:844)
> 	at scala.concurrent.impl.Future$PromiseCompletingRunnable.liftedTree1$1(Future.scala:24)
> 	at scala.concurrent.impl.Future$PromiseCompletingRunnable.run(Future.scala:24)
> 	at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:41)
> 	at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:401)
> 	at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
> 	at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.pollAndExecAll(ForkJoinPool.java:1253)
> 	at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1346)
> 	at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
> 	at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
> Caused by: java.lang.RuntimeException: Could not extract key from org.sample.flink.examples.Test$C@5e1a8111
> 	at org.apache.flink.streaming.runtime.io.RecordWriterOutput.collect(RecordWriterOutput.java:75)
> 	at org.apache.flink.streaming.runtime.io.RecordWriterOutput.collect(RecordWriterOutput.java:39)
> 	at org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:746)
> 	at org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:724)
> 	at org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collect(StreamSourceContexts.java:84)
> 	at org.apache.flink.streaming.api.functions.source.FromElementsFunction.run(FromElementsFunction.java:127)
> 	at org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:75)
> 	at org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:56)
> 	at org.apache.flink.streaming.runtime.tasks.SourceStreamTask.run(SourceStreamTask.java:56)
> 	at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:269)
> 	at org.apache.flink.runtime.taskmanager.Task.run(Task.java:655)
> 	at java.lang.Thread.run(Thread.java:745)
> Caused by: java.lang.RuntimeException: Could not extract key from org.sample.flink.examples.Test$C@5e1a8111
> 	at org.apache.flink.streaming.runtime.partitioner.KeyGroupStreamPartitioner.selectChannels(KeyGroupStreamPartitioner.java:61)
> 	at org.apache.flink.streaming.runtime.partitioner.KeyGroupStreamPartitioner.selectChannels(KeyGroupStreamPartitioner.java:32)
> 	at org.apache.flink.runtime.io.network.api.writer.RecordWriter.emit(RecordWriter.java:83)
> 	at org.apache.flink.streaming.runtime.io.StreamRecordWriter.emit(StreamRecordWriter.java:86)
> 	at org.apache.flink.streaming.runtime.io.RecordWriterOutput.collect(RecordWriterOutput.java:72)
> 	... 11 more
> Caused by: java.lang.ClassCastException: org.sample.flink.examples.Test$C cannot be cast to org.sample.flink.examples.Test$B
> 	at org.apache.flink.streaming.runtime.partitioner.KeyGroupStreamPartitioner.selectChannels(KeyGroupStreamPartitioner.java:59)
> 	... 15 more{code}
> This problem occurs when we use method reference as KeySelector. And there are no problems when we use anonymous class or lambda.



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