desktop - how to set an alarm in java -

i'm trying use java open default web browser youtube video @ specific time enter program (to make alarm of sorts)

here's code:

import java.awt.desktop; import java.net.uri; import java.net.urisyntaxexception; import java.io.ioexception;   public class ytalarm {     int hr;     int min;     public ytalarm(int hours, int minutes) //constructor      {         hr = hours;         min = minutes;     }      public static void main (string [] args) throws urisyntaxexception, ioexception //main method     {          string url = "https://www.youtube.com"; //link open once alarm goes off           ytalarm ytalarm = new ytalarm(15, 20); //sets alarm go off @ 3:20 pm          long alarm1 = ytalarm.converttimetomilli(); //converts alarm time ms           //checks time on each itteration , once alarm1== curent time, opens yt video         {              if (system.currenttimemillis() == alarm1)              {                 if (desktop.isdesktopsupported())                 {                      desktop.getdesktop().browse(new uri(url));                 }              }          }           while (system.currenttimemillis()!= time);      }      public long converttimetomilli() //method convert alarm time hours , minutes ms     {          long milli = (60000*min) + (3600000*hr);          return milli;     } } 

this code compiles no errors doesn't function properly. doesn't open link have entered when current time matches time entered constructor. know how can change code functions way intend to?