public static  void appendEscapingCDATA(StringBuffer buf,
    String str) 
{
      if (str != null) {
          int end = str.indexOf(CDATA_END);
          if (end <  0) {
              buf.append(str);
          } else {
              int start = 0;
              while (end  > -1) {
                  buf.append(str.substring(start, end));
                  buf.append(CDATA_EMBEDED_END);
                  start = end + CDATA_END_LEN;
                  if (start <  str.length()) {
                      end = str.indexOf(CDATA_END, start);
                  } else {
                      return;
                  }
              }
              buf.append(str.substring(start));
          }
      }
}

Ensures that embeded CDEnd strings (]]>) are handled properly within message, NDC and throwable tag text.

 public static String escapeTags(String input) 
{
                                                 
    //Check if the string is null, zero length or devoid of special characters
    // if so, return what was sent in.
    if(input == null
       || input.length() == 0
       || (input.indexOf('"") == -1 &&
           input.indexOf('&") == -1 &&
           input.indexOf('< ") == -1 &&
           input.indexOf(' >") == -1)) {
      return input;
    }
    //Use a StringBuffer in lieu of String concatenation -- it is
    //much more efficient this way.
    StringBuffer buf = new StringBuffer(input.length() + 6);
    char ch = ' ";
    int len = input.length();
    for(int i=0; i <  len; i++) {
      ch = input.charAt(i);
      if (ch  > ' >") {
          buf.append(ch);
      } else if(ch == '< ") {
	      buf.append("<");
      } else if(ch == ' >") {
	      buf.append(">");
      } else if(ch == '&") {
	      buf.append("&");
      } else if(ch == '"") {
	      buf.append(""");
      } else {
	      buf.append(ch);
      }
    }
    return buf.toString();
}

This method takes a string which may contain HTML tags (ie, <b>, <table>, etc) and replaces any '<', '>' , '&' or '"' characters with respective predefined entity references.