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scalaakka-streamalpakka

FileTailSource throws null pointer exception

I wrote the following Alpakka code

val fs = FileSystems.getDefault
val resource = getClass.getResource("countrycapital.csv")
val source = FileTailSource.lines(Paths.get(resource.toURI), maxLineSize = 8092, pollingInterval = 10000 seconds)

I have a file called "countrycapital.csv" in the src/main/resources folder.

My objective is to build a Akka Streams Source for this file and process all the records of this file.

when I run this code. the list line throws an exception

[error] (run-main-0) java.lang.NullPointerException
java.lang.NullPointerException
        at com.abhi.ElasticAkkaStreams$.delayedEndpoint$com$abhi$ElasticAkkaStreams$1(ElasticAkkaStreams.scala:37)
        at com.abhi.ElasticAkkaStreams$delayedInit$body.apply(ElasticAkkaStreams.scala:28)
        at scala.Function0.apply$mcV$sp(Function0.scala:34)
        at scala.Function0.apply$mcV$sp$(Function0.scala:34)
        at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
        at scala.App.$anonfun$main$1$adapted(App.scala:76)
        at scala.collection.immutable.List.foreach(List.scala:389)

I have imported the following libraries in my build.sbt

"com.lightbend.akka" %% "akka-stream-alpakka-elasticsearch" % "0.13",
"com.lightbend.akka" %% "akka-stream-alpakka-csv" % "0.13",
"com.lightbend.akka" %% "akka-stream-alpakka-file" % "0.13"
Solution

  • OK. I solved this myself

    I didn't have a / when picking the file path.

    This works without the null pointer exception

    val resource = getClass.getResource("/countrycapital.csv")