类/抽象类不支持多重继承，但scala .Why中的特征支持多重继承？

Question

让我解释一下我在scala中对多重继承的观察：

在类的scala中，多重继承是不可能的。我可以理解这是由于“钻石问题”的http://stackoverflow.com/questions/2064880/diamond-problem，所以下面的代码不能编译

    class High {
  def confuse(){
    println("High::I will confuse you later")
   }
}
class MiddleLeft extends High {
  override def confuse(){
    println("MiddleLeft::I will confuse you later")
   }
}
class MiddleRight extends High{
 override def confuse(){
    println("MiddleRight::I will confuse you later")
   }
}

// Below code does not compile
class LowLeft extends MiddleRight  with MiddleLeft{
  def calConfuse(){
    confuse()
  }
}

现在，特征可能有了具体的类。但它支持多重继承，因为特征如何扩展的顺序关系到解决菱形问题的顺序，因此下面的代码可以正常工作

trait High {
  def confuse(){
    println("High::I will confuse you later")
   }
}
trait MiddleLeft extends High {
  override def confuse(){
    println("MiddleLeft::I will confuse you later")
   }
}
trait MiddleRight extends High{
 override def confuse(){
    println("MiddleRight::I will confuse you later")
   }
}

class LowLeft extends MiddleRight  with MiddleLeft{
  def calConfuse(){
    confuse()
  }
}
class LowRight extends MiddleLeft with MiddleRight{
  def calConfuse(){
    confuse()
  }
}

object ConfuseTester extends App{
  val lowLeft:LowLeft=new LowLeft()
  lowLeft.confuse() //prints>>>MiddleLeft::I will confuse you later
  val lowRight:LowRight=new LowRight()
  lowRight.confuse()//prints>>>MiddleRight::I will confuse you later
}

我的问题是，为什么类的多重继承不像特征那样遵循相同的策略(如何扩展的顺序)

Answer 1

每个Scala类都被编译成一个JVM类，并且JVM不支持类的多重继承。