see http://mindprod.com/jgloss/calendar.html

You will use SimpleDateFormat

That would be American format, we English prefer our dates in sequential order
rather than inside-out order.

Use DateFormat and Local.

For example:

package tests;

import java.text.DateFormat;
import java.util.Date;
import java.util.Locale;

public class FormatDate {
 public static void main(String[] args) {
   Locale american = new Locale("en", "US" );
   Locale german = new Locale("de", "DE");
       
   DateFormat americanFormat =
     DateFormat.getDateInstance(DateFormat.SHORT, american);
   DateFormat germanFormat =
     DateFormat.getDateInstance(DateFormat.SHORT, german);
       
   Date date = new Date();
       
   System.out.println(americanFormat.format(date));
   System.out.println(germanFormat.format(date));
 }
}

will produce the following output:
3/18/08
18.03.08

As for getting the time, I'll leave that as an exercise for the student...