code: private static boolean followingCharsAre(String str, int startIndex, String nextChars) {
          return (str.indexOf(nextChars, startIndex + 1) == (startIndex + 1));
      }
docs: Tests if the chars following position {@code startIndex} in string
  {@code str} are that of {@code nextChars}.
  
  @param str
  @param startIndex
  @param nextChars
  @return