<? extends T> 与 <? super T>的区别，求解
import java.util.ArrayList;
import java.util.List;
public class Test {
public static void main(String[] args) throws SQLException {
List<? super Fruit> f0=new ArrayList<Fruit>();
f0.add(new Apple());
f0.add(new Fruit());
f0.add(new SupApple());
List<? super Fruit> f1=new ArrayList<Apple>();
f1.add(new Apple());
f1.add(new Fruit());
List<? extends Fruit> f2=new ArrayList<Fruit>();
f2.add(new Apple());
f2.add(new Fruit());
List<? extends Fruit> f3=new ArrayList<Apple>();
f3.add(new Apple());
f3.add(new Fruit());
// f.add(new Apple());
List<? super Apple> f5=new ArrayList<Fruit>();
f5.add(new Apple());
f5.add(new SupApple());
f5.add(new Fruit());
}
}
class Fruit{
}
class Apple extends Fruit{
}
class SupApple extends Apple{
}
