Date,DateFormat,Calendar,

String birth = "1993-03-06"; // set date

SimpleDateFormat s = new SimpeDateFormat ( "yyyy-MM-dd"); // set format

Date b = s.parse (birth); // create objects date

long btime = b.getTime (); // ms Switch

long now = new Date () getTime;. // Get the current date into milliseconds

long days = (now-btime) / 1000/60/60/24; // calculate the number of days into milliseconds.

Calendar:

Calendar c=new Calendar()

The number of milliseconds to create calenday object:

long ctime=c.getTime().getTime();