получение java .lang.ExceptionInInitializerError при разборе json

Question

Я отправляю json на мой scala код, но я получаю ошибку ``, когда json анализируется.

{"practice-question":{"title":"dummy title","description":"<p>some D</p><p><strong>with bold</strong></p><ol><li><strong>no 1</strong></li></ol>","tags":["javascript"],"references":["dummy references"],"hints":["<p><u>some hint</u></p>"],"image":["data:image/png;base64,iVBORw0],"answer":[{"filename":"c.js","answer":"function c(){\n    c;\n}"}],"success-test":"dummy success test","fail-test":"dummy fail test"}}))

Проверка json начинается с

 val questionOption = jsonBody.validateOpt[Question] //should give JsSuccess or JsError

Это должно вызвать следующее Reads

 implicit val questionReads:Reads[Question] = (JsPath \ "practice-question").read[PracticeQuestion](PracticeQuestionReads)
        .map((x:PracticeQuestion)=>Question.apply (x))

Reads для PracticeQuestion равно

implicit object PracticeQuestionReads extends Reads[PracticeQuestion] {
    def reads(json:JsValue):JsResult[PracticeQuestion]  =  {
      println(s"validating json ${json}")
      val structurallyValidated = json.validateOpt[PracticeQuestion](practiceQuestionValidateStructureReads) //check that structurally the json maps to PracticeQuestion
      println(s"structurally validated ${structurallyValidated}")
      val structuralValidationResult = structurallyValidated match {
        case JsSuccess(questionOpt,path)=>{
          val result = questionOpt.map(question=>{
              //TODOM - should check size of other lists (hints, references etc.)
            if(question.image.length <0 || question.image.length > 3)
            {
              JsError("invalid no. of images")
            }
            else {
              JsSuccess(question)
            }
          }).getOrElse(JsError("Error in validating Json"))
          result
        }
        case JsError(errors) =>{
          //TODOM - replace print with logger.
          println("errors in json structure: "+errors)
          JsError(errors)
        }
      }

      structuralValidationResult match {
        case JsSuccess(question,path)=>{
          //TODOM - check that for other mandatory fields (esp in Lists)are not empty
          if(question.answer.length == 0){
            JsError("Missing Answer")
          } else {
            JsSuccess(question);
          }
        }
        case JsError(errors) =>{
          JsError(errors)
        }
      }
    }
  }

и Reads, используемым в PracticeQuestionReads is

  implicit val practiceQuestionValidateStructureReads: Reads[PracticeQuestion] = {
    println("in conversion");
    val p =  //p is of type FunctionBuilder[Reads]#CanBuild. This is an intermediary object used to create Reads[PracticeQuestion].
    (JsPath \ "question-id").readNullable[UUID] and
      (JsPath \ "description").read[String] and
      (JsPath \ "hints").read[List[String]] and
      (JsPath \ "image").read[List[String]] and //while image data is optional, this field is always present i.e. will get at least image:[]
      (JsPath \ "success-test").read[String] and
      (JsPath \ "fail-test").read[String] and
      (JsPath \ "tags").read[Set[String]] and
      (JsPath \ "title").read[String] and
      (JsPath \ "answer").read[List[AnswerSection]] and
      (JsPath \ "references").read[List[String]] and
      (JsPath \ "question-creator").readNullable[QuestionCreator] and
      (JsPath \ "creation-year").readNullable[Long] and //year/month are for internal consumption so not worried about receiving it from a client
      (JsPath \ "creation-month").readNullable[Long] and
      (JsPath \ "creation-hour").readNullable[Long] and
      (JsPath \ "creation-minute").readNullable[Long]
    //apply method of CanBuildX with a function to translate individual values to your model, this will return your complex Reads
   val q = p.apply((PracticeQuestion.apply _))

    q

  }

Мне структура et c. смотри хорошо Что я делаю не так?