Hi,
Did anyone see java.util.ConcurrentModificationException when using
broadcast variables?
I encountered this exception when wrapping a Kafka producer like this in
the spark streaming driver.
Here is what I did.
KafkaProducer<String, String> producer = new KafkaProducer<String,
String>(properties);
final Broadcast<KafkaDataProducer> bCastProducer
= streamingContext.sparkContext().broadcast(producer);
Then within an closure called by a foreachRDD, I was trying to get the
wrapped producer, i.e.
KafkaProducer<String, String> p = bCastProducer.value();
after rebuilding and rerunning, I got the stack trace like this
Exception in thread "main" com.esotericsoftware.kryo.KryoException:
java.util.ConcurrentModificationException
Serialization trace:
classes (sun.misc.Launcher$AppClassLoader)
classloader (java.security.ProtectionDomain)
context (java.security.AccessControlContext)
acc (org.apache.spark.util.MutableURLClassLoader)
contextClassLoader (org.apache.kafka.common.utils.KafkaThread)
ioThread (org.apache.kafka.clients.producer.KafkaProducer)
producer ("my driver")
at
com.esotericsoftware.kryo.serializers.FieldSerializer$ObjectField.write(FieldSerializer.java:585)
at
com.esotericsoftware.kryo.serializers.FieldSerializer.write(FieldSerializer.java:213)
at com.esotericsoftware.kryo.Kryo.writeObject(Kryo.java:501)
at
com.esotericsoftware.kryo.serializers.FieldSerializer$ObjectField.write(FieldSerializer.java:564)
at
com.esotericsoftware.kryo.serializers.FieldSerializer.write(FieldSerializer.java:213)
at com.esotericsoftware.kryo.Kryo.writeClassAndObject(Kryo.java:568)
at
com.esotericsoftware.kryo.serializers.DefaultArraySerializers$ObjectArraySerializer.write(DefaultArraySerializers.java:318)
at
com.esotericsoftware.kryo.serializers.DefaultArraySerializers$ObjectArraySerializer.write(DefaultArraySerializers.java:293)
at com.esotericsoftware.kryo.Kryo.writeObject(Kryo.java:501)
at
com.esotericsoftware.kryo.serializers.FieldSerializer$ObjectField.write(FieldSerializer.java:564)
at
com.esotericsoftware.kryo.serializers.FieldSerializer.write(FieldSerializer.java:213)
at com.esotericsoftware.kryo.Kryo.writeObjectOrNull(Kryo.java:549)
at
com.esotericsoftware.kryo.serializers.FieldSerializer$ObjectField.write(FieldSerializer.java:570)
at
com.esotericsoftware.kryo.serializers.FieldSerializer.write(FieldSerializer.java:213)
at com.esotericsoftware.kryo.Kryo.writeObject(Kryo.java:501)
at
com.esotericsoftware.kryo.serializers.FieldSerializer$ObjectField.write(FieldSerializer.java:564)
at
com.esotericsoftware.kryo.serializers.FieldSerializer.write(FieldSerializer.java:213)
at com.esotericsoftware.kryo.Kryo.writeObject(Kryo.java:501)
at
com.esotericsoftware.kryo.serializers.FieldSerializer$ObjectField.write(FieldSerializer.java:564)
at
com.esotericsoftware.kryo.serializers.FieldSerializer.write(FieldSerializer.java:213)
at com.esotericsoftware.kryo.Kryo.writeObject(Kryo.java:501)
at
com.esotericsoftware.kryo.serializers.FieldSerializer$ObjectField.write(FieldSerializer.java:564)
at
com.esotericsoftware.kryo.serializers.FieldSerializer.write(FieldSerializer.java:213)
at com.esotericsoftware.kryo.Kryo.writeClassAndObject(Kryo.java:568)
at
org.apache.spark.serializer.KryoSerializationStream.writeObject(KryoSerializer.scala:148)
at
org.apache.spark.broadcast.TorrentBroadcast$.blockifyObject(TorrentBroadcast.scala:203)
at
org.apache.spark.broadcast.TorrentBroadcast.writeBlocks(TorrentBroadcast.scala:102)
at
org.apache.spark.broadcast.TorrentBroadcast.<init>(TorrentBroadcast.scala:85)
at
org.apache.spark.broadcast.TorrentBroadcastFactory.newBroadcast(TorrentBroadcastFactory.scala:34)
at
org.apache.spark.broadcast.BroadcastManager.newBroadcast(BroadcastManager.scala:62)
at org.apache.spark.SparkContext.broadcast(SparkContext.scala:1289)
at
org.apache.spark.api.java.JavaSparkContext.broadcast(JavaSparkContext.scala:648)
at "my driver"
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at
org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:664)
at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:169)
at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:192)
at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:111)
at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
Caused by: java.util.ConcurrentModificationException
at java.util.Vector$Itr.checkForComodification(Vector.java:1156)
at java.util.Vector$Itr.next(Vector.java:1133)
at
com.esotericsoftware.kryo.serializers.CollectionSerializer.write(CollectionSerializer.java:67)
at
com.esotericsoftware.kryo.serializers.CollectionSerializer.write(CollectionSerializer.java:18)
at com.esotericsoftware.kryo.Kryo.writeObject(Kryo.java:501)
at
com.esotericsoftware.kryo.serializers.FieldSerializer$ObjectField.write(FieldSerializer.java:564)
... 41 more
Thanks.
--
Regards,
Shenghua (Daniel) Wan
