Check out example codes for "add second to date java". It will help you in understanding the concepts better.

Code Example 1

/*  w  w w  .  j  a va  2s .  c om*/
import java.util.Calendar;
import java.util.Date;

public class Main {

  public static void main(String[] args) {
    System.out.println(addSeconds(new Date(), 100));
  }

  public static Date addSeconds(Date date, Integer seconds) {
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.add(Calendar.SECOND, seconds);
    return cal.getTime();
  }
}

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