Java or calculated current time with the number of days specified time difference between the two dates strings

. 1   public  static  void main (String [] args) throws a ParseException {
 2          / ** 
. 3           * Get the current time
 . 4           *
 . 5           * / 
. 6          a Date DATE = new new a Date ();
 . 7          / ** converter output formats mentioned date * / 
. 8          the SimpleDateFormat = the dateFormat new new the SimpleDateFormat ( "the mM-dd-YYYY HH: mm: SS" );
 . 9  
10  
. 11          string A = "2020-01-01"; // time string 
12 is          string B = dateFormat.format (DATE);
 13 is  
14         Between_dayInteger = Long between_days (A, B);
 15  
16          System.out.println (between_dayInteger);
 . 17  
18 is      }
 . 19  
20 is      public  static Long between_days (A String, String B) {
 21 is  
22 is          the SimpleDateFormat SimpleDateFormat = new new the SimpleDateFormat ( "the MM-YYYY -dd "); // custom time format 
23 is  
24          calendar calendar_a Calendar.getInstance = (); // Get a calendar object 
25          calendar calendar_b = Calendar.getInstance ();
 26 is  
27          a Date date_a = null ;
28          a Date date_b = null ;
 29  
30          the try {
 31 is              date_a = simpleDateFormat.parse (A); // string transfer a Date 
32              date_b = simpleDateFormat.parse (B);
 33 is              calendar_a.setTime (date_a); // Set the calendar 
34 is              calendar_b .setTime (date_b);
 35          } the catch (a ParseException E) {
 36              e.printStackTrace (); // format abnormality 
37 [          }
 38 is  
39          Long Time_A = calendar_a.getTimeInMillis ();
40          Long Time_B = calendar_b.getTimeInMillis ();
 41 is  
42 is          Long between_days = (Time_B - Time_A) / (1000 * 3600 * 24); // difference day_count_convention 
43 is  
44 is          return between_days;
 45      }