scala: abstract classes instantiation?

Question

How it comes that I instantiate an abstract class?

  abstract class A {
    val a: Int
  }

  val a = new A {val a = 3}

Or is some concrete cla

Answer 1

If you know Java, this is similar to:

new SomeAbstractClass() {
    // possible necessary implementation
}

Due to Scalas uniform access it looks like you're not implementing any abstract functions, but just by giving a a value, you actually do "concretesize" the class.

In other words, you're creating an instance of a concrete subclass of A without giving the subclass a name (thus the term "anonymous" class).