向下转型一定是new子类的对象，再转型；不能new父类的对象

Person p = new Man();
Man m = (Man)p;

 

 

integer i = new integer(1);
integer j = new integer(1);
i == j;//false

integer m = 1;
integer n = 1;
m == n;//ture

integer x = 128;//相当于new了integer对象
integer y = 128;//相当于new了integer对象

x == y;//false

自动装箱和new有什么区别？

 

 

 

 

 

 

Integer inScore = (Integer)obj;
int score = inScore;