void main() {
  print(SuperClass.create(true).runtimeType);
  print(SuperClass.create(false).runtimeType);
}

class SuperClass {
  SuperClass();
  factory SuperClass.create(bool createSubclass1) {
    if (createSubclass1) {
      return Subclass1();
    } else {
      return Subclass2();
    }
  }
}

class Subclass1 extends SuperClass {}

class Subclass2 extends SuperClass {}