[java泛型] 泛型的继承规则

前言

泛型的继承规则，跟类的继承规则是有点区别的，希望大家不要误解

测试类

public class Animal {}public class Dog extends Animal {}

List<Animal>可以引用 List<Dog>吗?

public class AnimalTest {    @Test    public void test01(){        List<Dog> list = new ArrayList<>();        List<Animal> list1 = list; //ERROR    }}

答案是不可以，其关系如下

继承关系

代码验证

public class AnimalTest {    @Test    public void test01() {        ArrayList<Dog> dogs = new ArrayList<>();        ArrayList<Animal> animals = new ArrayList<>();        ArrayList arrayList = dogs;        arrayList = dogs;        List<Dog> ldogs = dogs;        List<Animal> lanimal = animals;        List list = dogs;        list = animals;        list = arrayList;    }}

参考文献

《Java核心技术卷一》