//Class类
class classname{
}
classname obj=new classname();
Class c1=classname.class;
Class c2=obj.getClass();
Class c3=Class.forName(classname);
//c1c2c3是classname的类类型(class type)
//new是静态加载类
//Class.forName是动态加载类
classname obj1=(classname)c1.newInstance;
//使用类类型实例化对象 并做类型转换
