java - 是否可以使用 clon() 方法而不覆盖它

Question

我和我的老师遇到了一些麻烦，我们必须在大约一个月内掌握java的概念，他说以下是可能的:

所以在Java中每个类都继承自Object类，这个类为我们提供了诸如protected Object clone()之类的方法，例如:现在假设我们有类Car

//稍后在 main 中:

Car mycar=new Car();
//he is saying now that  following is possible:
Car yourCar=(Car) mycar.clone();

但网上的每篇文章都说这是不可能的，即使我尝试编译它也是不可能的，首先因为该方法受到保护，其次因为它会抛出异常

我有什么遗漏的吗？

Answer 1

是的，只要类实现 Cloneable，您就可以使用 .clone() 而无需覆盖它。

这是一个例子:

class Car implements Cloneable {
  String name;
  public Car(String n) {
    name = n;
  }

  public static void main(String[] args) throws Exception {
    Car c1 = new Car("Lightning McQueen");
    Car c2 = (Car) c1.clone();
    System.out.println(c2.name);
  }
}

这是default behavior of clone()的描述当类实现 Cloneable 但不重写 clone() 时:

this method creates a new instance of the class of this object and initializes all its fields with exactly the contents of the corresponding fields of this object, as if by assignment; the contents of the fields are not themselves cloned. Thus, this method performs a "shallow copy" of this object, not a "deep copy" operation.