java: Generating unique sequence of numbers

Calendar calendar = Calendar.getInstance(TimeZone.getDefault());

//generate a unique sequential number. We derive this from the
//number of milliseconds since 00:00:00 GMT Jan. 1, 1970 using //calendar object.
String runNumber = new Long(calendar.getTime().getTime()).toString();

System.out.println(runNumber);

java: Sorting Dates in a List (Collection)

final String DATE_FORMAT = "dd/MM/yy";
SimpleDateFormat dateFormat = new SimpleDateFormat(DATE_FORMAT);
dateFormat.setTimeZone(TimeZone.getDefault());

//we store date as time in milliseconds.
//getTime() returns the number of milliseconds since
//midnight of January 1, 1970. This method is also very
//useful for generating a unique sequence of numbers.
Long date0 = new Long(dateFormat.parse("29/01/1995").getTime());
Long date1 = new Long(dateFormat.parse("13/12/2007").getTime());
Long date2 = new Long(dateFormat.parse("01/04/2000").getTime());

List dateList = new ArrayList();
dateList.add(date0);
dateList.add(date1);
dateList.add(date2);

Collections.sort(dateList);

//Get wrapper Long from list. convert Long to String. 
//Convert String to primitive long. Convert primitive long to Date.
Date dateLatest = new Date(Long.parseLong(((Long) dateList.get(dateList.size()-1)).toString()));
String dateLatestString = dateFormat.format(dateLatest);

System.out.println(dateLatestString);

javascript: Sorting Date in an Array (Collection)

function getDateLatest()
{
  var date0 = new Date('12/31/2005');
  var date1 = new Date('11/29/2007');
  var date2 = new Date('01/13/1999');
  
  var dateArray = new Array();

  //we store date as time in milliseconds.
  //getTime() returns the number of milliseconds since
  //midnight of January 1, 1970. This method is also very
  //useful for generating a unique sequence of numbers.
  dateArray[0] = date0.getTime();
  dateArray[1] = date1.getTime();
  dateArray[2] = date2.getTime();
  dateArray.sort(sortNumber);

  var dateLatest = new Date(dateArray[dateArray.length - 1]);
  alert(dateLatest);}        

  //By default, Array sorts alphabetically.  To get it to sort
  //numerically, we write a function that compares numbers.
  function sortNumber(a, b)
  {
     return a - b
  }