I use the following softwares:
- Cassandra 2.1.9
- Spark 1.5
- Java using the Cassandra driver provided by Datastax.
- 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:
- spark-assembly-1.5.0-hadoop2.6.0.jar --> Comes with Spark download
- 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.
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.
来源：https://stackoverflow.com/questions/32606639/apache-spark-1-5-with-cassandra-class-cast-exception