add hour in date java code example

Example 1: java Calendar add time

Calendar calendar = Calendar.getInstance();  
// 15 days ago
calendar.add(Calendar.DATE, -15); 
// After 4 months
calendar.add(Calendar.MONTH, 4);

Example 2: add one day to current timestamp date in java

import java.sql.Timestamp;
import java.util.Calendar;
import java.util.Date;
 
public class AddTime {
  public static void main( String[] args ) {
 
    Timestamp timestamp = new Timestamp(new Date().getTime());
    System.out.println(timestamp);
 
    Calendar cal = Calendar.getInstance();
    cal.setTimeInMillis(timestamp.getTime());
 
    // add 30 seconds
    cal.add(Calendar.SECOND, 30);
    timestamp = new Timestamp(cal.getTime().getTime());
    System.out.println(timestamp);
 
    // add 5 hours
    cal.setTimeInMillis(timestamp.getTime());
    cal.add(Calendar.HOUR, 5);
    timestamp = new Timestamp(cal.getTime().getTime());
    System.out.println(timestamp);
 
    // add 30 days
    cal.setTimeInMillis(timestamp.getTime());
    cal.add(Calendar.DAY_OF_MONTH, 30);
    timestamp = new Timestamp(cal.getTime().getTime());
    System.out.println(timestamp);
 
    // add 6 months
    cal.setTimeInMillis(timestamp.getTime());
    cal.add(Calendar.MONTH, 6);
    timestamp = new Timestamp(cal.getTime().getTime());
    System.out.println(timestamp);
  }
}