gistfile1.scala

 case class JPlayer(id: Int, x: Int, y: Int)

    val players: ImmutableBag[Entity] = world.getManager(classOf[GroupManager]).getEntities("PLAYERS");
    val numEntities = players.size
    var entityJString : String = "["


    var aPlayers: ArrayBuffer[JPlayer] = ArrayBuffer()
    
    for( i <- 0 until numEntities) {

        val tempEntity : Entity = players.get(i)
        val tempPos : Position = tempEntity.getComponent(classOf[Position])
        val tempId = tempEntity.getId()
        aPlayers += JPlayer(tempId, tempPos.x, tempPos.y)
        
        //entityJString += "{id:" + tempId + ", x: " + tempPos.x + ", y: " + tempPos.y + "},\n"
    }

    entityJString += "]"
    val json = ("players" -> aPlayers.toList.map{ p =>
    (("id" -> p.id) ~
     ("x" -> p.x) ~
     ("y" -> p.y))})

    println(compact(render(json)))