code: public static boolean caseIgnoreMatch(String s1, String s2) {
          if (s1 == s2) {
              return true;
          }
  
          int len = s1.length();
          if (len != s2.length()) {
              return false;
          }
  
          for (int i = 0; i < len; i++) {
              char c1 = s1.charAt(i);
              char c2 = s2.charAt(i);
              if (c1 != c2 && toLower(c1) != toLower(c2)) {
                  return false;
              }
          }
          return true;
      }
docs: Compares two ASCII Strings s1 and s2, ignoring case.