HowTo use DateFormat static field constants ?

[Graeme Byers]

How are the static fields of DateFormat (inherited by SimpleDateFormat)such as DAY_OF_YEAR intended to be used (example please)? Could I use it to build a Julian date ?
Thank you.

    
public static final int DAY_OF_YEAR_FIELD Useful constant for DAY_OF_YEAR field alignment. Used in FieldPosition of date/time formatting. 

[Carey Evans]

DAY_OF_YEAR_FIELD, etc., can be used to return the position at which a data field was formatted. DAY_OF_YEAR_FIELD is SimpleDateFormat's %D, which is not very common. For YEAR_FIELD:

DateFormat fmt = DateFormat.getDateTimeInstance(DateFormat.FULL, DateFormat.FULL);
FieldPosition posn = new FieldPosition(DateFormat.YEAR_FIELD);
StringBuffer sb = new StringBuffer();
fmt.format(new Date(), sb, posn);
sb.replace(posn.getBeginIndex(), posn.getEndIndex(), "xxxx");
System.out.println(sb);

It doesn't look like this will help with Julian dates.