assigning an int to a char

[Abu Yoosuf]

Greetings all!
Just landed here. Like to know why the following code snippets behave differently.
{
final int i = 127;
char ic = i;
}

{
int j =127;
char jc = j; //this line complains and don't know why
}
thanks.

[R K Singh]

because int is not final.
At compile time integer should be final then only you can assign without casting.

[Arpana Rai]

Abu,
In the 1st block int varaible i is declared final.It means i is constant n its value can't be changed.so compilor don't raise any problen when i is assigned to char type varaible.
But in the 2nd block, int variable is not declared final.so we can change it's value and the new value can be out of range of char type.So compilor give error here.
regds
Arpana

[Abu Yoosuf]

why final behaves differently? int (32 bits) is assigned to a char (16 bits) - a narrow conversion - shouldn't it require a cast to char before the assignment on both snippets.

[Ron Newman]

Since i is final the compiler knows its value, and can determine whether or not the value will fit.
If you change it to
final int i = 70000;
the compiler will complain, because 70000 is
out of range for a character.

[Abu Yoosuf]

Ravi and Arpana,
Thanks for the replies.
Arpana,
I tried to use your explanation to find out whether it works for objects.
class A {}
class B extends A {}
class C
{
public static void main (String [] args)
{
//according to you, at this point the compiler knows a is pointing to a B instance
final A a = new B();
//so I expect the following assignment to work without a cast

B b = a; //but compiler complains ???

[Ron Newman]

I'm pretty sure this only works for primitives, not objects. Also, it only works for compile-time constants. This, for instance, won't work:
final int i = Math.round(2.4f);
char c = i;
[ November 14, 2002: Message edited by: Ron Newman ]

[Abu Yoosuf]

Thanks Ron.