java loop through string

String s = "...stuff...";

for (int i = 0; i < s.length(); i++){
    char c = s.charAt(i);        
    //Process char
}

String s = "...stuff...";

for (int i = 0; i < s.length(); i++){
    char c = s.charAt(i);        
    //Process char
}

for(int i = 0, n = s.length() ; i < n ; i++) { 
    char c = s.charAt(i); 
}