java.io.InvalidClassException: no valid constructor scala

Question

I am stuck with java.io.InvalidClassException: no valid constructor using Scala. I read about this exception I found that when trying to deserialize an object of serialized class the no_arg constructor is fired and if this constructor is not existed this exception throws. And I already have this no-arg constructor in my code but still, have this exception.

Here is my class:

object KB {

class KB(var UrlOwlFile: String, rdd: OWLAxiomsRDD, sparkSession: SparkSession) extends Serializable {

    var ontology: OWLOntology = initKB()
    var reasoner: OWLReasoner = _
    var hermit: Reasoner = _
    var manager: OWLOntologyManager = _
    var Concepts: RDD[OWLClass] = _
    var Roles: RDD[OWLObjectProperty] = _
    var dataFactory: OWLDataFactory = _
    var Examples: RDD[OWLIndividual] = _
    var dataPropertiesValue: RDD[RDD[OWLLiteral]] = _
    var Properties: RDD[OWLDataProperty] = _
    var domain: Array[Array[OWLIndividual]] = _
    var classifications: RDD[((OWLClassExpression, OWLIndividual), Int)]= _
    var newEle: ((OWLClassExpression, OWLIndividual), Int) = _

  def KB(){
      var ontology: OWLOntology = null
      var reasoner: OWLReasoner = null
      var hermit: Reasoner = null
      var manager: OWLOntologyManager = null
      var Concepts: RDD[OWLClass] = null
      var Roles: RDD[OWLObjectProperty] = null
      var dataFactory: OWLDataFactory = null
      var Examples: RDD[OWLIndividual] = null
      var dataPropertiesValue: RDD[RDD[OWLLiteral]] = null
      var Properties: RDD[OWLDataProperty] = null
      var domain: Array[Array[OWLIndividual]] = null
      var classifications: RDD[((OWLClassExpression, OWLIndividual), Int)]= null
      var newEle: ((OWLClassExpression, OWLIndividual), Int) = null
      val d: Double = 0.3
      var generator: Random = new Random(2)
    }
def getClassMembershipResult(testConcepts: Array[OWLClassExpression], negTestConcepts: Array[OWLClassExpression],
                                 examples: RDD[OWLIndividual]): RDD[((OWLClassExpression, OWLIndividual), Int)] = {

      println("\nClassifying all examples \n ------------ ")

      var flag: Boolean = false
      println("Processed concepts (" + testConcepts.size + "): \n")

      for (c <- 0 until testConcepts.size) {
        var p: Int = 0
        var n: Int = 0
        println("\nTest Concept number " + (c+1) + ": " + testConcepts(c))

        var c1 = examples.map{ x => (testConcepts(c),x)}
        var newEle1 = c1.map{x => (x, 0)}
        var c2 = newEle1.mapPartitions{data => data.map{ele => 
          if (getReasoner.isEntailed(getDataFactory.getOWLClassAssertionAxiom(testConcepts(c), ele._1._2))){
            newEle = (ele._1, +1)
            p = p + 1
          }
          else {
                if (!flag){
                  if (getReasoner.isEntailed(getDataFactory.getOWLClassAssertionAxiom(negTestConcepts(c), ele._1._2)))
                     newEle = (ele._1, -1)  
                }
                else
                     newEle = (ele._1, -1)  
                n = n + 1
              }
          println("\n Pos: " + p + "\t Neg: " + n)  

          newEle  
         }
        }

        classifications = c2
     }
      classifications.take(10).foreach(println(_))
      classifications
    }
    }
}

and here is the output:

18/03/23 11:10:09 ERROR Executor: Exception in task 0.0 in stage 36.0 (TID 44)
java.io.InvalidClassException: net.sansa_stack.ml.spark.classification.KB$KB$$anon$2; no valid constructor
    at java.io.ObjectStreamClass$ExceptionInfo.newInvalidClassException(ObjectStreamClass.java:157)
    at java.io.ObjectStreamClass.checkDeserialize(ObjectStreamClass.java:862)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2034)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:427)
    at org.apache.spark.serializer.JavaDeserializationStream.readObject(JavaSerializer.scala:75)
    at org.apache.spark.serializer.JavaSerializerInstance.deserialize(JavaSerializer.scala:114)
    at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:80)
    at org.apache.spark.scheduler.Task.run(Task.scala:99)
    at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:322)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
18/03/23 11:10:09 ERROR TaskSetManager: Task 0 in stage 36.0 failed 1 times; aborting job
Exception in thread "main" org.apache.spark.SparkException: Job aborted due to stage failure: Task 0 in stage 36.0 failed 1 times, most recent failure: Lost task 0.0 in stage 36.0 (TID 44, localhost, executor driver): java.io.InvalidClassException: net.sansa_stack.ml.spark.classification.KB$KB$$anon$2; no valid constructor
    at java.io.ObjectStreamClass$ExceptionInfo.newInvalidClassException(ObjectStreamClass.java:157)
    at java.io.ObjectStreamClass.checkDeserialize(ObjectStreamClass.java:862)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2034)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:427)
    at org.apache.spark.serializer.JavaDeserializationStream.readObject(JavaSerializer.scala:75)
    at org.apache.spark.serializer.JavaSerializerInstance.deserialize(JavaSerializer.scala:114)
    at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:80)
    at org.apache.spark.scheduler.Task.run(Task.scala:99)
    at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:322)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

Driver stacktrace:
    at org.apache.spark.scheduler.DAGScheduler.org$apache$spark$scheduler$DAGScheduler$$failJobAndIndependentStages(DAGScheduler.scala:1435)
    at org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1423)
    at org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1422)
    at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
    at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:48)
    at org.apache.spark.scheduler.DAGScheduler.abortStage(DAGScheduler.scala:1422)
    at org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskSetFailed$1.apply(DAGScheduler.scala:802)
    at org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskSetFailed$1.apply(DAGScheduler.scala:802)
    at scala.Option.foreach(Option.scala:257)
    at org.apache.spark.scheduler.DAGScheduler.handleTaskSetFailed(DAGScheduler.scala:802)
    at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.doOnReceive(DAGScheduler.scala:1650)
    at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.onReceive(DAGScheduler.scala:1605)
    at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.onReceive(DAGScheduler.scala:1594)
    at org.apache.spark.util.EventLoop$$anon$1.run(EventLoop.scala:48)
    at org.apache.spark.scheduler.DAGScheduler.runJob(DAGScheduler.scala:628)
    at org.apache.spark.SparkContext.runJob(SparkContext.scala:1925)
    at org.apache.spark.SparkContext.runJob(SparkContext.scala:1938)
    at org.apache.spark.SparkContext.runJob(SparkContext.scala:1951)
    at org.apache.spark.rdd.RDD$$anonfun$take$1.apply(RDD.scala:1354)
    at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:151)
    at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:112)
    at org.apache.spark.rdd.RDD.withScope(RDD.scala:362)
    at org.apache.spark.rdd.RDD.take(RDD.scala:1327)
    at net.sansa_stack.ml.spark.classification.KB$KB.getClassMembershipResult(KB.scala:226)
    at net.sansa_stack.ml.spark.classification.ClassMembership$ClassMembership.<init>(ClassMembership.scala:48)
    at net.sansa_stack.ml.spark.classification.TermDecisionTrees$.main(TermDecisionTrees.scala:47)
    at net.sansa_stack.ml.spark.classification.TermDecisionTrees.main(TermDecisionTrees.scala)
Caused by: java.io.InvalidClassException: net.sansa_stack.ml.spark.classification.KB$KB$$anon$2; no valid constructor
    at java.io.ObjectStreamClass$ExceptionInfo.newInvalidClassException(ObjectStreamClass.java:157)
    at java.io.ObjectStreamClass.checkDeserialize(ObjectStreamClass.java:862)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2034)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2278)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2202)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2060)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:427)
    at org.apache.spark.serializer.JavaDeserializationStream.readObject(JavaSerializer.scala:75)
    at org.apache.spark.serializer.JavaSerializerInstance.deserialize(JavaSerializer.scala:114)
    at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:80)
    at org.apache.spark.scheduler.Task.run(Task.scala:99)
    at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:322)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

Answer 1

There are two major problem with your code.

First in scala, the secondary constructor is defined like this:

class Greeter(message: String, secondaryMessage: String) {
    def this(message: String) = this(message, "")   //Secondary constructor      
    def SayHi() = println(message + secondaryMessage)
}

So your secondary constructor definition is incorrect. Use def this and call the primary constructor (which is the class definition i.e KB(var UrlOwlFile: String, rdd: OWLAxiomsRDD, sparkSession: SparkSession) from the secondary constructor. Furthermore, def KB() is treated like a method in the class KB and not as a constructor. As @Andrey already mentioned in the comments, looks at this for more information.

Secondly,

def KB(){
  var ontology: OWLOntology = null
  var ontology: OWLOntology = null
  var reasoner: OWLReasoner = null
  ....

var ontology declares a new variable inside the function KB() and it has nothing to do with variable ontology defined in the class KB. To re-initialize the ontology variable, simply use:

ontology = null

Also using null is a bad programming practice and in scala you can use Option instead.