gistfile1.scala

// cheap way to deep clone an arbitrarily-deep nested array
def deepCopy[T](array: Array[T]): Array[T] = {
  import java.io._
  val bos = new ByteArrayOutputStream()
  val oos = new ObjectOutputStream(bos)
  oos.writeObject(array)
  val bis = new ByteArrayInputStream(bos.toByteArray)
  val ois = new ObjectInputStream(bis)
  ois.readObject().asInstanceOf[Array[T]]
}

scala> val a = Array(Array(1,2,3), Array(4,5,6), Array(7,8,9))
a: Array[Array[Int]] = Array(Array(1, 2, 3), Array(4, 5, 6), Array(7, 8, 9))

scala> val c = deepCopy(a)
c: Array[Array[Int]] = Array(Array(1, 2, 3), Array(4, 5, 6), Array(7, 8, 9))

scala> a(0)(0) = 9999

scala> a
res3: Array[Array[Int]] = Array(Array(9999, 2, 3), Array(4, 5, 6), Array(7, 8, 9))

scala> c
res4: Array[Array[Int]] = Array(Array(1, 2, 3), Array(4, 5, 6), Array(7, 8, 9))