This example formats the time into 24 hour format (00:00-24:00) by using sdf.format(date) method of SimpleDateFormat class.

import java.text.SimpleDateFormat;
import java.util.Date;

public class Main {
   public static void main(String[] args) {
      Date date = new Date();
      SimpleDateFormat sdf = new SimpleDateFormat("h");
      System.out.println("hour in h format : "
      + sdf.format(date));
   }
}