boxing

[vini singh]

 
class Eggs  {
    int doX(Long x,Long y){return 1;}    
    int doX(long... x){return 2;}    
    int doX(Integer x,Integer y){return 3;}   
    int doX(Number n,Number m){return 4;}   
     public static void main(String s[])    {
     new Eggs().go(); 
     }
     void go()
     {      short s=7;
      System.out.println(doX(s,s));     
      System.out.println(doX (7,7)); 
     } 

output: DoX(s,s)=4 doX(7,7)=3
as boxing is preffered against widening i think answer should be doX(s,s)=3 but then why its dox(s,s)=4 and the reason given is boxing and then widening as its a one step process. i really cant understand help me out please explain.what do they mean by one step process

(Jesper Young: Added code tags)
[ December 11, 2008: Message edited by: Jesper Young ]

[subhasish nag]

In

  doX(s,s)  

compiler will chose

  doX(Number n,Number m){return 4;}   

because here short only need to be boxed to Short.Where in

  doX(Integer x,Integer y){return 3;}   

compiler need to first widen then Box it to Integer.
So clearly choice one is prefferable.

[ December 10, 2008: Message edited by: subhasish nag ]
[ December 11, 2008: Message edited by: subhasish nag ]

[Jesper de Jong]

Please use code tags when you post code - that will make it much easier to read.

[subhasish nag]

Thanks Jesper.

[Ankit Garg]

Originally posted by subhasish nag:
compiler need to first widen then Box it to Integer.
So clearly choice one is prefferable.

It's not about which is preferable. You CANNOT widen and then box. So these are illegal

int   -> Long    //error
short -> Integer //error
float -> Double  //error

But boxing and then widening is allowed. So these are legal

int   -> Number
long  -> Number
short -> Object
int   -> Object