companion-object.scala

object Foo {
  var initialized = 0

  // This only happens once regardless of how many times Foo.fetch() is called
  initialized = initialized + 1

  def fetch(): Integer = initialized
}

class Foo {
  println(s"initialized: ${Foo.fetch()}")
}

new Foo // prints "initialized: 1"
new Foo // prints "initialized: 1"
new Foo // prints "initialized: 1"