Class cannot be created (missing no-arg constructor): scala.collection.immutable.Map

[Maatary]

I keep getting the following error

Exception in thread "main" com.esotericsoftware.kryo.KryoException: Class cannot be created (missing no-arg constructor): scala.collection.immutable.Map
at com.esotericsoftware.kryo.Kryo$DefaultInstantiatorStrategy.newInstantiatorOf(Kryo.java:1319)
at com.esotericsoftware.kryo.Kryo.newInstantiator(Kryo.java:1127)
at com.esotericsoftware.kryo.Kryo.newInstance(Kryo.java:1136)
at com.romix.scala.serialization.kryo.ScalaImmutableMapSerializer.read(ScalaMapSerializers.scala:75)
at com.romix.scala.serialization.kryo.ScalaImmutableMapSerializer.read(ScalaMapSerializers.scala:69)
at com.esotericsoftware.kryo.Kryo.readObject(Kryo.java:709)
at entellect.spike.Kryo.KryoSpike$.delayedEndpoint$entellect$spike$Kryo$KryoSpike$1(KryoSpike.scala:25)
at entellect.spike.Kryo.KryoSpike$delayedInit$body.apply(KryoSpike.scala:10)
at scala.Function0$class.apply$mcV$sp(Function0.scala:34)
at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
at scala.App$$anonfun$main$1.apply(App.scala:76)
at scala.App$$anonfun$main$1.apply(App.scala:76)
at scala.collection.immutable.List.foreach(List.scala:392)
at scala.collection.generic.TraversableForwarder$class.foreach(TraversableForwarder.scala:35)
at scala.App$class.main(App.scala:76)
at entellect.spike.Kryo.KryoSpike$.main(KryoSpike.scala:10)
at entellect.spike.Kryo.KryoSpike.main(KryoSpike.scala)

package entellect.spike.Kryo

import java.io.{ByteArrayInputStream, ByteArrayOutputStream}

import com.esotericsoftware.kryo.Kryo
import com.esotericsoftware.kryo.io.{Input, Output}
import com.romix.scala.serialization.kryo.ScalaImmutableMapSerializer

object KryoSpike extends App {

  val kryo = new Kryo()
  kryo.addDefaultSerializer(classOf[scala.collection.Map[_,_]], classOf[ScalaImmutableMapSerializer])
  kryo.addDefaultSerializer(classOf[scala.collection.generic.MapFactory[scala.collection.Map]], classOf[ScalaImmutableMapSerializer])

  val testin = Map("id" -> "objID", "field1" -> "field1Value")

  val outStream = new ByteArrayOutputStream()
  val output = new Output(outStream, 4096)
  kryo.writeClassAndObject(output, testin)
  output.flush()


  val input = new Input(new ByteArrayInputStream(outStream.toByteArray), 4096)
  val testout = kryo.readObject(input, classOf[Map[String,String]])

  println(testout.toString)
}

I originally tried with:

    kryo.addDefaultSerializer(classOf[scala.collection.Map[_,_]], classOf[ScalaMapSerializer])
    kryo.addDefaultSerializer(classOf[scala.collection.generic.MapFactory[scala.collection.Map]], classOf[ScalaMapSerializer])

But this does not compile. Indeed, the compiler can't find the class ScalaMapSerializer.

Please can someone help with this ?

[luben]

Try adding serializer for the concrete classes. You need something like: https://github.com/romix/akka-kryo-serialization/blob/master/src/main/scala/com/romix/akka/serialization/kryo/KryoSerializer.scala#L397

Explanation: scala.collection.Map is just a trait - the deserializer should know the exact class that you want to deserialize.