why I cann't assign FINAL INT to Byte

[Jack Crifer]

final int i = 1;
byte b1 = i;//1
Byte b2 = i;//2    

When the int is -128 to 127,the compiler will treat it as an byte. Just like code in line 1 is OK,but why line 2 is complie error?

[Ulf Dittmer]

Because you can't assign an object of type Integer to a reference of type Byte. Autoboxing doesn't mean that the left side is unboxed to "byte", it means that the right side is boxed to Integer.

[Satya Maheshwari]

Originally posted by Ulf Dittmer:
Because you can't assign an object of type Integer to a reference of type Byte. Autoboxing doesn't mean that the left side is unboxed to "byte", it means that the right side is boxed to Integer.

Hi Ulf
Somehow I am unable to replicate the compilation error mentioned. The following code is compiling just fine for me.

public class Demo {
public static void main(String[] args) {
final int i =100;
byte b = i;
Byte b1 = i;
}
 
}

I am using JDK 1.6 . Could you please point me if I am missing something here?
[ July 07, 2008: Message edited by: Satya Maheshwari ]

[Jack Crifer]

final int i = 1;
//Byte b = new Byte(i); [B]//Here is complie error[/B]
Byte b = i; [B]//Here is runtime error[/B]   

and Byte b = new Byte(2); is complie error too.

who can explian it .

[kapil kumar]

final int i = 1;//
Byte b = new Byte(i); //Here is complie error
Byte b = i; //Here is runtime error

Hi...
Here i is a compile time constant..
When you say Byte b = new Byte(i);,here i is an integer literal while Byte() expects either a byte value or a string val...
So when we change this to:

Byte b = new Byte((byte)i); or Byte b = new Byte("10");it works fine but for Byte b = new Byte(10); it does not since 10 is an integer literal...

for Byte b = i; it compiles n runs fine....

[Sunny Mattas]

public class Demo
{
public static void main(String args[])
{
final int i =100;
byte b = i;
Byte b1 = i;//runtime error.
}
}

Somebody please explain why.........
Byte b = i is giving runtime error/exception.
error/exception is:
Exception in thread "main" java.lang.VerifyError: (class: Demo, method: main signature: ([Ljava/lang/String V) Register 1 contains wrong type

Regards
Sunny

[Raphael Rabadan]

The following code won't give any error using a 1.5/1.6 jre:

final int i = 1;
byte b1 = i;//1
Byte b2 = i;//2      

a final int between -128 and 127 will be seen as a byte, therefore making the code above correct.

Please, those with error take a look what jre you'r using to compile.
[ July 09, 2008: Message edited by: Raphael Rabadan ]