code: private static boolean matches16(CharSequence s, int start, final String t, int length) {
          int end = start + length;
          while (length-- > 0) {
              if (s.charAt(--end) != t.charAt(length)) {
                  return false;
              }
          }
          return true;
      }
docs: Compare strings without any argument checks. Requires length>0.