if (languages == null || languages.length == 0) {
if (languages == null) {
    public void setContentLanguage(String[] languages) throws MessagingException {        if (languages == null || languages.length == 0) {            removeHeader("Content-Language");        } else if (languages.length == 1) {            setHeader("Content-Language", languages[0]);        } else {            StringBuffer buf = new StringBuffer(languages.length * 20);            buf.append(languages[0]);            for (int i = 1; i < languages.length; i++) {                buf.append(',').append(languages[i]);            }            setHeader("Content-Language", buf.toString());        }    }