static String checkCDATASection(final String data) {
    String reason;
    if ((reason = checkCharacterData(data)) != null) {
      return reason;
    }

    if (data.contains("]]>")) {
      return "CDATA cannot internally contain a CDATA ending " +
             "delimiter (]]>)";
    }

    // If we got here, everything is OK
    return null;
  }
static String checkCDATASection(final String data)