NoSuchMethodError on akka.persistence.Persistence.journalFor private API

[dgouyette]

Hello,

I prepare a workshop on akka-persistence (Code is available here : https://github.com/dgouyette/workshop-akka-persistence )

When i use the ReadJournal :

    val readJournal = PersistenceQuery(actorSystem).readJournalFor[PostgresReadJournal](PostgresReadJournal.Identifier).eventsByPersistenceId("", 0, Long.MaxValue)
    val readJournalAsJsValue = readJournal.map( _.event).collect{case e : BoardEvent=>  Json.parse(eventJsonEncoder.toJson(e).value)   }
    Flow.fromSinkAndSource(Sink.ignore, readJournalAsJsValue)
  }

I got the following exception :

a.a.OneForOneStrategy - head of empty list
java.util.NoSuchElementException: head of empty list
	at scala.collection.immutable.Nil$.head(List.scala:428)
	at scala.collection.immutable.Nil$.head(List.scala:425)
	at akka.actor.ActorCell.receiveMessage(ActorCell.scala:588)
	at akka.actor.ActorCell.invoke(ActorCell.scala:557)
	at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:258)
	at akka.dispatch.Mailbox.run(Mailbox.scala:225)
	at akka.dispatch.Mailbox.exec(Mailbox.scala:235)
	at akka.dispatch.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
	at akka.dispatch.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
	at akka.dispatch.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
java.lang.NoSuchMethodError: akka.persistence.Persistence.journalFor(Ljava/lang/String;)Lakka/actor/ActorRef;
	at akka.persistence.pg.journal.query.BaseEventsPublisher.<init>(BaseEventsPublisher.scala:31)
	at akka.persistence.pg.journal.query.LiveEventsByPersistenceIdPublisher.<init>(LiveEventsByPersistenceIdPublisher.scala:15)
	at akka.persistence.pg.journal.query.package$EventsByPersistenceIdPublisher$.$anonfun$props$3(package.scala:44)
	at akka.actor.TypedCreatorFunctionConsumer.produce(IndirectActorProducer.scala:87)
	at akka.actor.Props.newActor(Props.scala:212)
	at akka.actor.ActorCell.newActor(ActorCell.scala:624)
	at akka.actor.ActorCell.create(ActorCell.scala:650)
	at akka.actor.ActorCell.invokeAll$1(ActorCell.scala:523)
	at akka.actor.ActorCell.systemInvoke(ActorCell.scala:545)
	at akka.dispatch.Mailbox.processAllSystemMessages(Mailbox.scala:283)
	at akka.dispatch.Mailbox.run(Mailbox.scala:224)
	at akka.dispatch.Mailbox.exec(Mailbox.scala:235)
	at akka.dispatch.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
	at akka.dispatch.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
	at akka.dispatch.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
	at akka.dispatch.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)

Persistence(context.system).journalFor(writeJournalPluginId) is a private API.

Is there a workaround ?
i use :

• akka 2.5.14
• akka-persistence-pg 0.10.0
• Scala 2.12

[kwark]

It looks like you are on akka 2.5.13 instead of 2.5.14 => https://github.com/dgouyette/workshop-akka-persistence/blob/master/build.sbt#L9

I'll check if we can replace calling the private API with something else

[dgouyette]

Thanks for you answer 👍
I made tests with versions from 2.5.10 to 2.5.17, same error.
Do you know if i can use a workaround ?

I replaced
val journal: ActorRef = Persistence(context.system).journalFor(writeJournalPluginId)
by
val journal: ActorRef = PersistenceQuery(context.system).readJournalFor(writeJournalPluginId)

But it doesn't work. :-(