java.lang.ClassCastException: class scala.collection.immutable.HashMap cannot be cast to class scala.collection.Factory

[davidnadeau]

Search before asking

• I had searched in the issues and found no similar issues.

Version

0.9.0

Component(s)

Other, Java

Minimal reproduce step

I am trying to deserialize into the scala type: Map[String, String].

What did you expect to see?

No error

What did you see instead?

Failed to deserialize key:
* binary data *
due to exception: java.lang.ClassCastException: class scala.collection.immutable.HashMap cannot be cast to class scala.collection.Factory (scala.collection.immutable.HashMap and scala.collection.Factory are in unnamed module of loader 'app')"

Anything Else?

This issue did not appear to be present in java jdk 17, but only when we upgraded to jdk 21. There are no errors with jdk 21 and fury 0.7.0.

In 0.9.0 i've started using the new Scala serializers

import org.apache.fury.serializer.scala.ScalaSerializers
ScalaSerializers.registerSerializers(fury)

I think there is an issue with the scala serializers.

Are you willing to submit a PR?

• I'm willing to submit a PR!

[chaokunyang]

@davidnadeau could you provide reproduction code?

[davidnadeau]

Hi @chaokunyang my fury config looks like:

  val fury = Fury
    .builder()
    .withScalaOptimizationEnabled(true)
    .requireClassRegistration(false)
    .withRefTracking(false)
    .buildThreadSafeFuryPool(Runtime.getRuntime.availableProcessors() * 2, Runtime.getRuntime.availableProcessors() * 2)

  ScalaSerializers.registerSerializers(fury)

[davidnadeau]

I am working to provide more details. I want to test 3 scenarios:

1. jdk 21 fury 0.9.0 fury_core dep
2. jdk 21 fury 0.9.0 fury_scala dep (no scala serializers)
3. jdk 21 fury 0.9.0 fury_scala dep + scala serializers

I will report back my findings. And try to provide a more detailed reproduction code, however I have a suspicion that it may be a thread race condition. Alongside the failures to deserialize I also saw other errors.

java.lang.ArrayIndexOutOfBoundsException

and

ERROR  ThreadPoolFury:84 [finagle/netty4-1-49] - null
java.lang.NullPointerException

[chaokunyang]

Hi @davidnadeau , I tested HashMap with jdk 21, it still works:

val v = scala.collection.immutable.HashMap("k1" -> "v1", "k2" -> "v2")
fury.deserialize(fury.serialize(v)) shouldEqual v