using replace() method

I have a String str = "12345678";
Can anyone tell me why :
str.replace('4', 'B'); will give me "123B5678"
but :
str.replace((char)4, 'B'); won't change str.

replace() requires a char parameter and I can't see anything wrong with casting an int to char.
Thanks for any help!
Paul

because (char)4 is not '4'.
Try this code -
System.out.println((char)4); //doesn't print 4
replace() method can't find character with unicode value 4 in the sting.
HTH,
- Manish

yes and replace('4','B'), will search for char '4' not for ((char)4) as they've diff values and then if found then replace it with 'B'. hope i helped