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https://issues.apache.org/jira/browse/SPARK-12407?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15074461#comment-15074461
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Shixiong Zhu edited comment on SPARK-12407 at 12/30/15 12:08 AM:
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The cause is Streaming checkpointing doesn't support Accumulators and Broadcast 
values.


was (Author: zsxwing):
The cause is Streaming checkpointing doesn't support Broadcast values.

> ClassCast Exception when restarting spark streaming from checkpoint
> -------------------------------------------------------------------
>
>                 Key: SPARK-12407
>                 URL: https://issues.apache.org/jira/browse/SPARK-12407
>             Project: Spark
>          Issue Type: Bug
>          Components: Streaming
>    Affects Versions: 1.5.1
>            Reporter: Bartlomiej Alberski
>
> I am receiving ClassCast Exception when restarting streaming application from 
> checkpoint:
> {code}
> java.lang.ClassCastException: [B cannot be cast to 
> pl.example.spark.StreamingTestReporter
>       at 
> pl.example.spark.StreamingTest$$anonfun$createContext$1$$anonfun$apply$2$$anonfun$apply$4$$anonfun$apply$5.apply(StreamingTest.scala:38)
>       at 
> pl.example.spark.StreamingTest$$anonfun$createContext$1$$anonfun$apply$2$$anonfun$apply$4$$anonfun$apply$5.apply(StreamingTest.scala:36)
>       at scala.collection.immutable.List.foreach(List.scala:318)
>       at 
> pl.example.spark.StreamingTest$$anonfun$createContext$1$$anonfun$apply$2$$anonfun$apply$4.apply(StreamingTest.scala:36)
>       at 
> pl.example.spark.StreamingTest$$anonfun$createContext$1$$anonfun$apply$2$$anonfun$apply$4.apply(StreamingTest.scala:33)
>       at 
> org.apache.spark.rdd.RDD$$anonfun$foreachPartition$1$$anonfun$apply$29.apply(RDD.scala:898)
>       at 
> org.apache.spark.rdd.RDD$$anonfun$foreachPartition$1$$anonfun$apply$29.apply(RDD.scala:898)
>       at 
> org.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1848)
>       at 
> org.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1848)
>       at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:66)
>       at org.apache.spark.scheduler.Task.run(Task.scala:88)
>       at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:214)
>       at 
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
>       at 
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
>       at java.lang.Thread.run(Thread.java:745)
> {code}
> It looks like the problem is connected with instance of class broadcasted to 
> the executors. I think that when restoring from checkpoint Id of broadcasted 
> value changes - this is the reason why read from broadcasted memory block 
> something else (instead of instance of our class). In my production code I 
> received sligthly different exception:
> {code}
> java.lang.ClassCastException: org.apache.spark.util.SerializableConfiguration 
> cannot be cast to com.example.sender.MyClassReporter
> {code}
> Below there are links for spark user list with discussion about issue as well 
> as minimal example that helps in reproducing issue.
> http://apache-spark-user-list.1001560.n3.nabble.com/Spark-streaming-java-lang-ClassCastException-org-apache-spark-util-SerializableConfiguration-on-restt-td25698.html
> https://github.com/alberskib/spark-streaming-broadcast-issue



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