Java long calculate elapsed time

public class Main {
  public static void main(String[] args) throws Exception {
    // Get current time
    long start = System.currentTimeMillis();
    System.out.println(start);// w ww. j  av  a  2  s .  c  o m
    // Do something ...
    start -= 124123123;
    

    // Get elapsed time in milliseconds
    long elapsedTimeMillis = System.currentTimeMillis() - start;
    System.out.println("elapsedTimeMillis:"+elapsedTimeMillis);
    // Get elapsed time in seconds
    float elapsedTimeSec = elapsedTimeMillis / 1000F;
    System.out.println("elapsedTimeSec:"+elapsedTimeSec);
    
    // Get elapsed time in minutes
    float elapsedTimeMin = elapsedTimeMillis / (60 * 1000F);
    System.out.println("elapsedTimeMin:"+elapsedTimeMin);
    
    // Get elapsed time in hours
    float elapsedTimeHour = elapsedTimeMillis / (60 * 60 * 1000F);
    System.out.println("elapsedTimeHour:"+elapsedTimeHour);
    
    // Get elapsed time in days
    float elapsedTimeDay = elapsedTimeMillis / (24 * 60 * 60 * 1000F);
    System.out.println("elapsedTimeDay:"+elapsedTimeDay);
  }
}