Convert date to long millseconds in java

/**
 * @author lautturi.com
 * Java example: get long millseconds from date string in java
 */

import java.util.*;
import java.text.ParseException;
import java.text.SimpleDateFormat;

public class Lautturi {

	public static void main(String[] args) {

		String string_date = "25-12-2019";

		SimpleDateFormat f = new SimpleDateFormat("dd-MM-yyyy");
		try {
		    Date d = f.parse(string_date);
		    long milliseconds = d.getTime();
		    
		    System.out.println("Date time in milliseconds: "+milliseconds);
		} catch (ParseException e) {
		    e.printStackTrace();
		}

	}
}

output:

Date time in milliseconds: 1577203200000