How To Convert Time And Date in unix timestamp in Java

import java.text.DateFormat;

import java.text.SimpleDateFormat;

import java.time.Instant;

import java.time.LocalDateTime;

import java.time.ZoneId;

import java.time.ZonedDateTime;

import java.util.Calendar;

import java.util.Date;

public class Java8Time {

public static void main(String args[]){

//TO convert current time to epoch time

LocalDateTime ldt = LocalDateTime.now();

ZonedDateTime zdt = ldt.atZone( ZoneId.systemDefault());

long millis = zdt.toInstant().toEpochMilli();

System.out.println("localdatetime to Epoch"+millis);

//To convert local date Time to Java.util.Date

Instant instant = ldt.atZone(ZoneId.systemDefault()).toInstant();

Date res = Date.from(instant);

System.out.println("local datetime to util date"+res);

//To convert epoch time to local date time

long value=1468474303146L;

LocalDateTime date =  LocalDateTime.ofInstant(Instant.ofEpochMilli(value),ZoneId.systemDefault());

System.out.println("epoch to localdatetime"+date);

//To convert Java Util Date to local date time

Date dt = new Date();

Instant instant1 = Instant.ofEpochMilli(dt.getTime());

LocalDateTime tm = LocalDateTime.ofInstant(instant, ZoneId.systemDefault());

System.out.println("date to localdatetime"+tm);

//Get epoch Time from calender instance

DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");

Calendar cal = Calendar.getInstance();

System.out.println("cal to epoch"+cal.getTimeInMillis());

//To convert String to java Util Date

String timestamp="2016/07/13 12:05:30";

DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");

try{

          Date tist=dateFormat.parse(timestamp);

System.out.println("String to javautil"+tist);

System.out.println("javautil to epoch"+tist.getTime());

}catch(Exception e){

System.out.println("Error"+e.getMessage());

}

}

}