How to Calculate the Difference Between Two Java Date Instances

There are times when we need to calculate the difference between two dates in Java.

Below is a simple Java Program which uses SimpleDateFormat and DecimalFormat Java APIs to perform this action.

getTime() returns the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this Date object.

package crunchify.com.tutorials;

import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * @author Crunchify.com
 * 
 */

public class CrunchifyTimeDiff {

	public static void main(String[] args) {
		try {
			String date1 = "07/15/2016";
			String time1 = "11:00 AM";
			String date2 = "07/17/2016";
			String time2 = "12:15 AM";

			String format = "MM/dd/yyyy hh:mm a";

			SimpleDateFormat sdf = new SimpleDateFormat(format);

			Date dateObj1 = sdf.parse(date1 + " " + time1);
			Date dateObj2 = sdf.parse(date2 + " " + time2);
			System.out.println(dateObj1);
			System.out.println(dateObj2 + "\n");

			DecimalFormat crunchifyFormatter = new DecimalFormat("###,###");

			// getTime() returns the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this Date object
			long diff = dateObj2.getTime() - dateObj1.getTime();

			int diffDays = (int) (diff / (24 * 60 * 60 * 1000));
			System.out.println("difference between days: " + diffDays);

			int diffhours = (int) (diff / (60 * 60 * 1000));
			System.out.println("difference between hours: " + crunchifyFormatter.format(diffhours));

			int diffmin = (int) (diff / (60 * 1000));
			System.out.println("difference between minutues: " + crunchifyFormatter.format(diffmin));

			int diffsec = (int) (diff / (1000));
			System.out.println("difference between seconds: " + crunchifyFormatter.format(diffsec));

			System.out.println("difference between milliseconds: " + crunchifyFormatter.format(diff));

		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

Another must read:

• Java: How to add “n” minutes to Calendar data object?
• Java StringTokenizer and String Split Example

Output:

Mon Jul 15 11:00:00 PDT 2013
Wed Jul 17 00:15:00 PDT 2013

difference between days: 1
difference between hours: 37
difference between minutes: 2,235
difference between seconds: 134,100
difference between milliseconds: 134,100,000