public static String filter(String message) {        if (message == null)            return (null);        char content[] = new char[message.length()];        message.getChars(0, message.length(), content, 0);        StringBuffer result = new StringBuffer(content.length + 50);        for (int i = 0; i < content.length; i++) {            switch (content[i]) {            case ‘<‘:                result.append("&lt;");                break;            case ‘>‘:                result.append("&gt;");                break;            case ‘&‘:                result.append("&amp;");                break;            case ‘"‘:                result.append("&quot;");                break;            default:                result.append(content[i]);            }        }        return (result.toString());    }