public static FastDateFormat getInstance
        (String pattern, Locale locale) throws IllegalArgumentException
    {
        return getInstance(pattern, null, locale, null);
    }
@param pattern {@link java.text.SimpleDateFormat} compatible pattern
@param locale optional locale, overrides system locale
@return the fast date format
xmppserver/src/main/java/org/jivesoftware/util/FastDateFormat.java