List,Set,Map在java.util包下都是接口
List有两个实现类:ArrayList和LinkedList
Set有两个实现类:HashSet和LinkedHashSet
AbstractSet实现了Set
Set有两个实现类:HashSet和LinkedHashSet
AbstractSet实现了Set
A:LinkedList实现了List接口;
B: AbstractSet实现了Set接口;
C: HashSet继承自AbstractSet基类;
D: WeakMap继承自 AbstractMap
![](https://images2015.cnblogs.com/blog/1089549/201706/1089549-20170610153211356-457013913.png)