Eu estou tentando serializar um mutávelPriorityQueue em scala (2.10) e estou recebendo umNotSerializableException ao gravar o objeto em um ObjectOutputStream. Eu fiz um caso de teste simples:

import java.io.{ByteArrayOutputStream, ObjectOutputStream}
import scala.collection.mutable

object Test extends App {
  val pq = new mutable.PriorityQueue[Int]()
  val oos = new ObjectOutputStream(new ByteArrayOutputStream())
  oos.writeObject(pq)
}

A exceção é

Exception in thread "main" java.io.NotSerializableException:scala.collection.mutable.PriorityQueue$ResizableArrayAccess
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1180)
at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1528)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1493)
at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1416)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1174)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:346)
at Test$.main(Test.scala:7)

Parece que um PriorityQueue deve ser serializável, há algo que eu possa fazer para contornar isso?