title: how to set a countdown timer for a specific time
body: <p>I have a class that is taking two time values and finding that a given time interval is present within the time range by using system's current time. Now I want to set a countdown timer which should calculate the time left for a particular time interval. Can anyone show me how to set a countdown timer for calculating the time left for 'exact time' in this code?</p>
  
  <pre><code>// start time
  String string1 = date + " 20:30:00";  
  Date time1 = new SimpleDateFormat("MM-dd-yyHH:mm:ss").parse(string1);
  Calendar calendar1 = Calendar.getInstance();
  calendar1.setTime(time1);
  
  // end time
  String string2 = date + " 06:30:00";  
  Date time2 = new SimpleDateFormat("MM-dd-yy HH:mm:ss").parse(string2);
  Calendar calendar2 = Calendar.getInstance();
  calendar2.setTime(time2);
  
  // exact time
  String string3 = date + " 04:36:00";
  Date F = new SimpleDateFormat("MM-dd-yy HH:mm:ss").parse(string3);
  Calendar c3 = Calendar.getInstance();
  c3.setTime(F);   
  </code></pre>