Comparing the json data types at runtime using Jackson and Scala

Question

I have an incoming JSON data that looks like below:

{"id":"1000","premium":29999,"eventTime":"2021-12-22 00:00:00"}

Now, I have created a class that will accept this record and will check whether the data type of the incoming record is according to the data types defined in the case class. However, when I am calling the method it is always calling the Failure part of the match case.

    case class Premium(id: String, premium: Long, eventTime: String)
    
    class Splitter extends ProcessFunction[String, Premium] {
      val outputTag = new OutputTag[String]("failed")
    
      def fromJson[T](json: String)(implicit m: Manifest[T]): Either[String, T] = {
        Try {
          println("inside")
          lazy val mapper = new ObjectMapper() with ScalaObjectMapper
          mapper.registerModule(DefaultScalaModule)
          mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
          mapper.readValue[T](json)
        } match {
          case Success(x) => {
            Right(x)
          }
          case Failure(err) => {
            Left(json)
          }
        }
      }
override def processElement(i: String, context: ProcessFunction[String, Premium]#Context, collector: Collector[Premium]): Unit = {
    fromJson(i) match {
      case Right(data) => {
        collector.collect(data)
        println("Good Records: " + data)
      }
      case Left(json) => {
        context.output(outputTag, json)
        println("Bad Records: " + json)
      }
    }
  }
    }

Based on the sample record above, it should pass the Success value but no matter what I pass, it always enters the Failure part. What else is missing?

I am using Scala 2.11.12 and I tried examples from this link and this link but no luck.