// ERROR: Exception in thread "AWT-EventQueue-0" java.lang.Error: Cannot call invokeAndWait from the event dispatcher thread


    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        showHelloThereDialog();
    }                                        
    
    
    public void showHelloThereDialog() {
        Runnable showModalDialog = new Runnable() {
            public void run() {
                try{
                    wait(500);
                    jLabel1.setText("safsadfsdf");
                } catch(InterruptedException e){ System.out.println("Sleep Interrupted"); }
            }
        };
        
        try {
            SwingUtilities.invokeAndWait  (showModalDialog);
        } catch(InvocationTargetException e){
            System.out.println("Sleep Interrupted");
        } catch(InterruptedException e){ System.out.println("Sleep Interrupted"); }
        
    }