Hashmap通用

Question

I want to create a hashmap where the key is of interface A, and the value is of interface B. Then I want to initialize it with classes that implements A and B. Is it possible to do it with java generics?

That is, I want to have something like

hashmap<<? implements A>, <? implements B>> _map;
_map.put(a1, b1);

where a1 implements A; and b1 implements B.

The original intent is that I want to create a factory, so that I can look up on a1 and return an instance of b1.

Answer 1

 Map<A, B> map = new HashMap<A, B>();
 map.put(a1, b1);

Answer 2

是的，有可能，这样写就足够了：

Map<A, B> _map = HashMap<A, B>();

Answer 3

this may be what you are looking for:

HashMap<A,B> map = new HashMap<A,B>();

map.put(a1,b1);