Scala: abstract classes instantiation with trait?

Question

This a example code in the book:

abstract class Check {
  def check():String = "Checked Application Details... "
}
trait EmploymentCheck extends Check{
  override def check():String = "Check Employment ... " + super.check()
}

val app = new Check with EmploymentCheck

Which make me confused is the new Check , How can we instantiation a abstract class ? And why it will work by with EmploymentCheck ?

Answer 1

new Check with EmploymentCheck generates an anonymous concrete subclass of Check . No abstract class is instantiated.

scala> app.getClass
res0: Class[_ <: EmploymentCheck] = class $anon$1

Answer 2

您要实例化的类型是Check with EmploymentCheck不是Check ，并且Check with EmploymentCheck不是抽象的，因为抽象成员的check已经由EmploymentCheck填写。