我环顾四周，到目前为止，还没有找到在Java中对同一通配符类型同时设置上下限的任何方法。我不确定是否有可能，并倾向于将它作为Java中通配符的当前限制。
下面是我要寻找的示例。
$(function () {
$('#AcceptUserAgreement').click(
onToggleRegisterUserDisabledClick
);
});
在public class A {}
public class B extends A{}
public class C extends B{}
public class D extends C{}
public static void main(String[] args)
{
List<A> a = Arrays.asList(new A());
List<B> b = Arrays.asList(new B());
List<C> c = Arrays.asList(new C());
List<D> d = Arrays.asList(new D());
extendsParam(a); // error as A is not assignable to B
extendsParam(b);
extendsParam(c);
extendsParam(d); // 3 previous ok as they can produce B
superParam(a);
superParam(b);
superParam(c); // 3 previous ok as they can consume C
superParam(d); // error as C is not assignable to D
extendsSuperParam(a); // error as A is not assignable to B
extendsSuperParam(b);
extendsSuperParam(c); // 2 previous ok as they can consume C and produce B
extendsSuperParam(d); // error as C is not assignable to D
}
public static void extendsParam(List<? extends B> blist)
{
B b = blist.get(0);
blist.add(new C()); // error
}
public static void superParam(List<? super C> clist)
{
B b = clist.get(0); // error
clist.add(new C());
}
public static void extendsSuperParam(List<???> bclist)
{
B b = bclist.get(0); // ok
bclist.add(new C()); // ok
}
类中查找通用类型信息，看起来它支持使用该信息定义类型。但是，我找不到用这种语言创建这种类型的方法。
是否缺少某些内容，或者是当前无法用Java语言描述的类型？