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Java：泛型，指向<；的超类类型引用；？扩展超类>；类型参考_Java_Generics - Fatal编程技术网
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Java：泛型，指向<；的超类类型引用；？扩展超类>；类型参考

java generics

Java：泛型，指向<；的超类类型引用；？扩展超类>；类型参考,java,generics,Java,Generics,在我试图编译的以下代码中： List<Animal> animals; List<? extends Animal> some; animals = some; 列出动物； 列表因为列表因为列表列表列表请参阅 列表请参见 ListListList Type mismatch: cannot convert from List<capture#2-of ? extends Animal> to List<Animal> List<Anima

在我试图编译的以下代码中：

List<Animal> animals;
List<? extends Animal> some;
animals = some;

列出动物；
列表因为
列表因为
列表
列表
列表请参阅


列表请参见


List
List
List

Type mismatch: cannot convert from List<capture#2-of ? extends Animal> to List<Animal>



List<Animal> cats = new List<Animal>();
cats.add(new Cat());
List<Dog> dogs = cats; //if was legal
dogs.add(new Dog)); //now you have a dog in a list of cats



Animal[] cats = new Animal[] {...};
Dogs[] dogs = cats; // OK at compile time



final List<? extends Animal> someAnimals = ...;
final List<Animal> animals = new ArrayList<Animal>(someAnimals);