Java gui/swingworker issue

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Java

Swing

GUI

Hi guys, I'm very new to java and I've been dealing with this issue for more then 10 days. I have an app to create with two options, on time and count down, where user chooses desired option, and on time set new window opens and it blinks changing colors. Option two works just fine, but option number on will not start at time defined.

This is code for first option:

if (jCheckBox1.isSelected()){
        st = true;
   
    set = jFormatted.getText();
    try{
     
     String myDateString = jFormatted.getText();
     SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
       Date date = sdf.parse(myDateString);
        date.toString();
       Calendar c = Calendar.getInstance();
            c.setTimeInMillis(razlika);
    }
       
    catch(Exception e){}
   
       sw = new SwingWorker() {  
            @Override
            protected Object doInBackground() throws Exception{
                Thread.sleep(razlika);
              
              Calendar c = Calendar.getInstance();
            c.setTimeInMillis(razlika);
           
              Thread.sleep(c.getTimeInMillis(),s.getTime1());
                FrameBoja.Pocetak();
                while(st){
                  Thread.sleep(s.getTime1()); 
                    FrameBoja.cf.getContentPane().setBackground(s.getColor());
                    Thread.sleep(s.getSpeed());
                     FrameBoja.cf.getContentPane().setBackground(new Color (44,62,80)); 
                      Thread.sleep(s.getSpeed());  
                     
                }
                return null;
            }
        }; 

and here it is for second one

else if(jCheckBox2.isSelected()){
        s.setTime2((Integer)jSpinner2.getValue()*1000);
        st = true;
        sw = new SwingWorker() {
            @Override
            protected Object doInBackground() throws Exception {
                Thread.sleep(s.getTime2());
                 FrameBoja.Pocetak();
                 while(st){
                     FrameBoja.cf.getContentPane().setBackground(s.getColor());  
                     Thread.sleep(s.getSpeed());
                     FrameBoja.cf.getContentPane().setBackground(new Color (44,62,80));
                     Thread.sleep(s.getSpeed());  
                 }
                 return null;
            }
        };
        sw.execute();


        sw.execute();

Any help, advice is more then welcome.

What I have tried:

I have tried a lots of things, changed time formatters, changed variables...