First Convert String date into simple Date formate
public String getconvertdate1(String date)
{
    DateFormat inputFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    inputFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
    DateFormat outputFormat = new SimpleDateFormat("dd MMM yyyy");
    Date parsed = new Date();
    try
    {
        parsed = inputFormat.parse(date);
    }
    catch (ParseException e)
    {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    String outputText = outputFormat.format(parsed);
    return outputText;
}
//now can do anything with date.
 long diff = today.getTimeInMillis() - thatDay.getTimeInMillis(); //result in millis
 long days = diff / (24 * 60 * 60 * 1000);// you get day difference between
AND use simpledateFormate to configure HH:MM:SS