Scala map is not Serializable

Question
1 
  def main(args: Array[String]): Unit =
    case class Person(var name: String, var age: Int)
    val p    = Person("123", 111)
    val map  = mutable.Map("p1" -> p, "p2" -> p)
    val map2 = SerializationUtils.clone(map)
    map2("p1").name = "xxx"
    println(map)
    println(map2)
    println()

Then how can I deep copy a scala map ?

2

I can’t use json serializers becaure I want to keep p1 and p2 pointing to the same person object.