具有接口的多态合法性与具有抽象类的多态合法性一样吗？

Question

For example:

Say you have an abstract class called Animal, and a non-abstract class called Dog. This is legal:

Animal dog = new Dog();

But if you have an interface called Car and a normal class called Toyota would the same be legal?

Car car = new Toyota();

Thanks!

Answer 1

Yes It is legal.

In your case, Dog must extend Animal:

abstract class Animal {}

class Dog extends Animal {}

The same is true with an interface (which is abstract by definition), and a class which implements it:

interface Car {}

class Toyota implements Car {}

Answer 2

是的，只要丰田实施Car，这当然是合法的。