Difference in days between two dates in Java?

Question

I need to find the number of days between two dates: one is from a report and one is the current date. My snippet:

  int age=calculateDifference(agingDate, today); 

Here calculateDifference is a private method, agingDate and today are Date objects, just for your clarification. I've followed two articles from a Java forum, Thread 1 / Thread 2.

It works fine in a standalone program although when I include this into my logic to read from the report I get an unusual difference in values.

Why is it happening and how can I fix it?

EDIT :

I'm getting a greater number of days compared to the actual amount of Days.

public static int calculateDifference(Date a, Date b) {     int tempDifference = 0;     int difference = 0;     Calendar earlier = Calendar.getInstance();     Calendar later = Calendar.getInstance();      if (a.compareTo(b) < 0)     {         earlier.setTime(a);         later.setTime(b);     }     else     {         earlier.setTime(b);         later.setTime(a);     }      while (earlier.get(Calendar.YEAR) != later.get(Calendar.YEAR))     {         tempDifference = 365 * (later.get(Calendar.YEAR) - earlier.get(Calendar.YEAR));         difference += tempDifference;          earlier.add(Calendar.DAY_OF_YEAR, tempDifference);     }      if (earlier.get(Calendar.DAY_OF_YEAR) != later.get(Calendar.DAY_OF_YEAR))     {         tempDifference = later.get(Calendar.DAY_OF_YEAR) - earlier.get(Calendar.DAY_OF_YEAR);         difference += tempDifference;          earlier.add(Calendar.DAY_OF_YEAR, tempDifference);     }      return difference; } 

Note :

Unfortunately, none of the answers helped me solve the problem. I've accomplished this problem with the help of Joda-time library.

Answer 1

I would suggest you use the excellent Joda Time library instead of the flawed java.util.Date and friends. You could simply write

import java.util.Date; import org.joda.time.DateTime; import org.joda.time.Days;  Date past = new Date(110, 5, 20); // June 20th, 2010 Date today = new Date(110, 6, 24); // July 24th  int days = Days.daysBetween(new DateTime(past), new DateTime(today)).getDays(); // => 34 

Answer 2

I might be too late to join the game but what the heck huh? :)

Do you think this is a threading issue? How are you using the output of this method for example? OR

Can we change your code to do something as simple as:

Calendar calendar1 = Calendar.getInstance();     Calendar calendar2 = Calendar.getInstance();     calendar1.set(<your earlier date>);     calendar2.set(<your current date>);     long milliseconds1 = calendar1.getTimeInMillis();     long milliseconds2 = calendar2.getTimeInMillis();     long diff = milliseconds2 - milliseconds1;     long diffSeconds = diff / 1000;     long diffMinutes = diff / (60 * 1000);     long diffHours = diff / (60 * 60 * 1000);     long diffDays = diff / (24 * 60 * 60 * 1000);     System.out.println("\nThe Date Different Example");     System.out.println("Time in milliseconds: " + diff  + " milliseconds.");     System.out.println("Time in seconds: " + diffSeconds  + " seconds.");     System.out.println("Time in minutes: " + diffMinutes  + " minutes.");     System.out.println("Time in hours: " + diffHours  + " hours.");     System.out.println("Time in days: " + diffDays  + " days.");   }