I apply a for loop to emphasize the string and use charAt() to arrange specific character to check it. Since the String is achieved with an array, the charAt() program is a regular time operation.
String s = "...stuff...";
for (int i = 0; i < s.length(); i++){
char c = s.charAt(i);
//Process char
}
That's something I would do. It appears the most obvious to me.
As far as precision goes, I don't think that endures here. It is all based on your style.