Widening and Boxing

[adithya narayan]

Hi,

I don't get as to why JAVA doesn't support Widening and then Boxing !!

For example:

class Test
{
     public static void main(String[] args) { 
     {
             byte b = 2;
	    new Test().widenAndBox(b);     
     }
}

Thanks,
Adithya.

[Hebert Coelho]

Where is this method "widenAndBox" declared?

[Sunny Bhandari]

Which version of JDK are you using? It has to be JDK 1.4 upwards...

[adithya narayan]

@sunny : i am using JDK 1.6.
@Hebert : sorry, i forgot to put the method . Here goes the complete code :

 class Test  
 {  
      public static void main(String[] args) {   
      {  
              byte b = 2;  
              new Test().widenAndBox(b);       
      }  
        
        void widenAndBox(Long num)
	{
		System.out.println(num);
	}
 } 

[Sunny Bhandari]

Seems like widen and box can't happen in one go. The following code works for me:

see the modification...

public final class FinalClassExample { 
  
public static void main(String[] args) throws Exception 
{		
    byte b = 2;  
    long l = b;
    new FinalClassExample().widenAndBox(l);       
}  

void widenAndBox(Long num)
{
System.out.println(num);
}
}

[Mohamed Sanaulla]

May be the language creators wanted it that way. And moreover Autoboxing was introduced in Java 5. And widening has been in place for a long time before. So widening is given more preference and hence- no widening and boxing together.

[Campbell Ritchie]

Mohamed Sanaulla wrote:May be the language creators wanted it that way. . . .

Agree. There are descriptions of conversions in the Java™ Language Specifications, and boxing and un-boxing stand on their own.