title: Why I get "Application does not take parameters" using JSON Read with Play framework 2.3?
body: <p>I wanna write JSON validation for a few Scala model classes in Play framework 2.3x. I'm using JSON Reads to do that following the instructions (<a href="https://playframework.com/documentation/2.3.x/ScalaJsonCombinators" rel="noreferrer">https://playframework.com/documentation/2.3.x/ScalaJsonCombinators</a>). But I get "Application does not take parameters" error and I don't know how to fix this.</p>
  
  <p>Here is my code.</p>
  
  <pre><code>package models
  
  import play.api.libs.json._
  import play.api.libs.json.Reads._
  import play.api.libs.functional.syntax._
  import reactivemongo.bson.BSONObjectID
  import java.util.Date
  
  case class ArtifactModel(
                            _id: BSONObjectID,
                            name: String,
                            createdAt: Date,
                            updatedAt: Date,
                            attributes: List[AttributeModel],
                            stateModels: List[StateModel])
  
  case class AttributeModel(
                             name: String,
                             comment: String)
  
  case class StateModel(
                         name: String,
                         comment: String)
  
  object ArtifactModel {
    implicit val artifactModelReads: Reads[ArtifactModel] = (
        (__ \ "_id").readNullable[String] ~
        (__ \ "name").read[String] ~
        (__ \ "createdAt").readNullable[Long] ~
        (__ \ "updatedAt").readNullable[Long] ~
        (__ \ "attributes").read[List[AttributeModel]] ~
        (__ \ "stateModels").read[List[StateModel]]
      )(ArtifactModel) // here is the error: "Application does not take parameters"
  
  
    implicit val attributeModelReads: Reads[AttributeModel] = (
        (__ \ "name").read[String] ~
        (__ \ "comment").read[String]
      )(AttributeModel)
  
    implicit val stateModelReads: Reads[StateModel] = (
        (__ \ "name").read[String] ~
        (__ \ "comment").read[String]
      )(StateModel)
  }
  </code></pre>
  
  <p>Can you help me? Any solution or suggestions for JSON validation in Scala/Play are appreciated. </p>