I have a break point set at line `s = new Array(capacity)` but it seems like the apply method is not being called. Have I implemented it correctly ?

```
object StacksAndQueuesTest {

    def main(args: Array[String]) {

      val f = new FixedCapacityStackOfStrings(3)
      println(f.isEmpty);

    }

}

class FixedCapacityStackOfStrings(capacity : Int) {

  var s : Array[String] = _
  var N : Int = 0

  def isEmpty : Boolean = {
    N == 0
  }

  def push(item : String) = {
    this.N = N + 1
    s(N) = item
  }

  def pop = {
    this.N = N - 1
    val item : String = s(N)

    /**
     * Setting this object to null so
     * that JVM garbage collection can clean it up
     */
    s(N) = null
    item
  }

  object FixedCapacityStackOfStrings {
  def apply(capacity : Int){
   s = new Array(capacity)
  }
}

}

```