用Scala包含的Java接口实现的工厂方法意味着什么？

trait Animal {
  def speak(): Unit
}

class Dog extends Animal {
  override def speak(): Unit = println("Woof!")
}

class Cat extends Animal {
  override def speak(): Unit = println("Meow!")
}

object AnimalFactory {
  def createAnimal(animalType: String): Animal = {
    animalType match {
      case "dog" => new Dog
      case "cat" => new Cat
      case _ => throw new IllegalArgumentException("Invalid animal type")
    }
  }
}

val dog = AnimalFactory.createAnimal("dog")
dog.speak() // Output: Woof!

val cat = AnimalFactory.createAnimal("cat")
cat.speak() // Output: Meow!