How to calculate number of days between two given dates

If you are looking for a utility method which computes the days between two given dates then you can use the following method

public static long daysBetweenDates(Date from, Date to) {
		return TimeUnit.DAYS.convert((to.getTime() - from.getTime()), TimeUnit.MILLISECONDS);
	}

Following is the complete Java program which uses the above method and prints days between given dates.

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.TimeUnit;

public class DaysBetweenDates {
	
	public static void main(String[] args) throws ParseException {
		
		Date from = new SimpleDateFormat("yyyy-MM-dd").parse("2017-09-01");
		Date to = new SimpleDateFormat("yyyy-MM-dd").parse("2017-10-01");

		System.out.println("Difference between dates is: " + daysBetweenDates(from, to));
	}

	public static long daysBetweenDates(Date from, Date to) {
		return TimeUnit.DAYS.convert((to.getTime() - from.getTime()), TimeUnit.MILLISECONDS);
	}
	
}

Output:

Difference between dates is: 30