code: public void setAcceptCharset(List<Charset> acceptableCharsets) {
  		StringBuilder builder = new StringBuilder();
  		for (Iterator<Charset> iterator = acceptableCharsets.iterator(); iterator.hasNext();) {
  			Charset charset = iterator.next();
  			builder.append(charset.name().toLowerCase(Locale.ENGLISH));
  			if (iterator.hasNext()) {
  				builder.append(", ");
  			}
  		}
  		set(ACCEPT_CHARSET, builder.toString());
  	}
docs: Set the list of acceptable {@linkplain Charset charsets},
  as specified by the {@code Accept-Charset} header.