What's the difference between abstraction and generalization?

Question

I understand that abstraction is about taking something more concrete and making it more abstract. That something may be either a data structure or a procedure. For example:

Answer 1

Not addressing credible / official source: an example in Scala

Having "Abstraction"

  trait AbstractContainer[E] { val value: E }

  object StringContainer extends AbstractContainer[String] {
    val value: String = "Unflexible"
  }

  class IntContainer(val value: Int = 6) extends AbstractContainer[Int]

  val stringContainer = new AbstractContainer[String] {
    val value = "Any string"
  }

and "Generalization"

  def specialized(c: StringContainer.type) =
    println("It's a StringContainer: " + c.value)

  def slightlyGeneralized(s: AbstractContainer[String]) =
    println("It's a String container: " + s.value)

  import scala.reflect.{ classTag, ClassTag }
  def generalized[E: ClassTag](a: AbstractContainer[E]) =
    println(s"It's a ${classTag[E].toString()} container: ${a.value}")

  import scala.language.reflectiveCalls
  def evenMoreGeneral(d: { def detail: Any }) =
    println("It's something detailed: " + d.detail)

executing

  specialized(StringContainer)
  slightlyGeneralized(stringContainer)
  generalized(new IntContainer(12))
  evenMoreGeneral(new { val detail = 3.141 })

leads to

It's a StringContainer: Unflexible
It's a String container: Any string
It's a Int container: 12
It's something detailed: 3.141