Program to calculate the time of sorting an array

import java.util.Arrays;
import java.util.Date;
public class Demo {
	public static void main(String[] args) {
		int[] arr = new int[1000];
		for (int i = 0; i<arr.length; i++) {
			arr[i] = (int) (i + 20);
		}
		Date past = new Date();
		Arrays.sort(arr);
		Date future = new Date();
		System.out.println("Time (milliseconds) = " + (future.getTime() - past.getTime()));
	}
}