1 引入泛型:延迟声明 2 如何声明和使用泛型 3 泛型的好处和原理 4 泛型类、泛型方法、泛型接口、泛型委托 5 泛型约束 6 协变 逆变(选修) 7 泛型缓存(选修)(1 introduction of generics: deferred declarations 2 how to declare and use generics 3 benefits and principles of generics 4 generic classes, generic method