A Null Object is an object that extends a base type with a null or neutral behavior. Here’s the Scala version of the Java example Wikipedia uses to demonstrate this:

trait Animal {
  def makeSound()
}

class Dog extends Animal {
  def makeSound() { println("woof") }
}

class NullAnimal extends Animal {
  def makeSound() {}
}

As you can imagine, later in your application you might have some code like this:

If you’ve never heard of the term DICEE, it was coined by Guy Kawasaki. Mr. Kawasaki was a developer evangelist for the original Macintosh team in the 1980s, and used the term in at least one subsequent book to refer to great products.

“DICEE” is an acronym that stands for Deep, Indulgent, Complete, Elegant, and Emotive: