小编Ste*_*han的帖子

任何人都可以告诉我为什么看跌期权给我一个错误？

static HashMap<Class, ? extends BaseSystem> systems;

public <T extends BaseSystem> EntityManager()//constructor
{
    systems=new HashMap<Class, T>();
} 

public static <T extends BaseSystem> void addSystem(Class c, T system)//store a system for later reference
{
    systems.put(c, system);
}