Apache Spark 1.5 with Cassandra : Class cast exception

2
votes

I use the following softwares:

  1. Cassandra 2.1.9
  2. Spark 1.5
  3. Java using the Cassandra driver provided by Datastax.
  4. Ubuntu 12.0.4

When I run spark locally using local[8], the program runs fine and data is saved into Cassandra. However, when I submit the job to spark cluster, the following exception is thrown:

16 Sep 2015 03:08:58,808  WARN [task-result-getter-0] (Logging.scala:71) TaskSetManager - Lost task 3.0 in stage 0.0 (TID 3,
192.168.50.131): java.lang.ClassCastException: cannot assign instance of scala.collection.immutable.HashMap$SerializationProxy to field scala.collection.Map$WithDefault.underlying of type scala.collection.Map in instance of scala.collection.immutable.Map$WithDefault
        at java.io.ObjectStreamClass$FieldReflector.setObjFieldValues(ObjectStreamClass.java:2083)
        at java.io.ObjectStreamClass.setObjFieldValues(ObjectStreamClass.java:1261)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1996)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
        at org.apache.spark.serializer.JavaDeserializationStream.readObject(JavaSerializer.scala:72)
        at org.apache.spark.serializer.JavaSerializerInstance.deserialize(JavaSerializer.scala:98)
        at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:61)
        at org.apache.spark.scheduler.Task.run(Task.scala:88)
        at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:214)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)

I am clueless how to fix this error. I use only the following 2 dependencies:

  1. spark-assembly-1.5.0-hadoop2.6.0.jar --> Comes with Spark download
  2. spark-cassandra-connector-java-assembly-1.5.0-M1-SNAPSHOT.jar --> Build from Git using sbt.

I have exported my bundled application jar into the spark classpath also. Kindly help as I am not sure if this is an application specific error or a problem with Spark distribution itself.

1
apache-sparkcassandra-2.0

1 Answers

2
votes

I found out the issue finally.

The problem was that I was only adding my bundled Application jar (fat jar) into the spark context and excluded the following two jars:

1. spark-assembly-1.5.0-hadoop2.6.0.jar

2. spark-cassandra-connector-java-assembly-1.5.0-M1-SNAPSHOT.jar.

It turns out that I should also add spark-cassandra-connector-java-assembly-1.5.0-M1-SNAPSHOT.jar to the spark context and only exclude the spark-assembly-1.5.0-hadoop2.6.0.jar.