code: public static String reverse(final String binaryStr) {
      final StringBuilder occupyBuffer = new StringBuilder(binaryStr.length());
      for (int i = 0; i < binaryStr.length(); i++) {
        if ('0' == binaryStr.charAt(i)) {
          occupyBuffer.append('1');
        } else {
          occupyBuffer.append('0');
        }
      }
      return occupyBuffer.toString();
    }
docs: <p>
  reverse.
  </p>
  
  @param binaryStr a {@link java.lang.String} object.
  @return a {@link java.lang.String} object.