code: public final static DateFormat getDateTimeInstance(int dateStyle,
                                                         int timeStyle)
      {
          return get(dateStyle, timeStyle, ULocale.getDefault(Category.FORMAT), null);
      }
docs: Returns the date/time formatter with the given date and time
  formatting styles for the default <code>FORMAT</code> locale.
  @param dateStyle the given date formatting style. For example,
  SHORT for "M/d/yy" in the US locale. As currently implemented, relative date
  formatting only affects a limited range of calendar days before or after the
  current date, based on the CLDR &lt;field type="day"&gt;/&lt;relative&gt; data: For example,
  in English, "Yesterday", "Today", and "Tomorrow". Outside of this range, relative
  dates are formatted using the corresponding non-relative style.
  @param timeStyle the given time formatting style. For example,
  SHORT for "h:mm a" in the US locale. Relative time styles are not currently
  supported, and behave just like the corresponding non-relative style.
  @return a date/time formatter.
  @see Category#FORMAT