So I am trying to use SwingWorkers in my application (written in Java) where I collect some data from an API and display it in the app’s GUI. Please keep in mind that I am very unsure when it comes to threads, it’s a concept I struggle to grasp and understand.

I will provide the method for which the thread is being run, I’m not sure what else I need to provide but do let me know if there’s more that needs to be shown in order for me to get help.

    private void initialThread() {
        dataUpdateTimer = new Timer(60 * 60 * 1000, new ActionListener() { // Update every hour
            
            @Override
            public void actionPerformed(ActionEvent e) {
                rg.getLoadingMsg(); // Display the JOptionPane message
                if (cachedChannelData != null) { //If the cached data is not null
                    cachedChannelData.clear(); //Clear the cached data to make new cache
                }
                rg.clearChannelTable(); //Clear the table displaying the channels (GUI)
                rg.clearGui(); //Clear the rest of the GUI
                SwingWorker<Void, Map<String, Map<String, programClass>>> sw = new SwingWorker<Void, Map<String, Map<String, programClass>>>() {
                    @Override
                    protected Void doInBackground() throws Exception {
                        cachedChannelData = cm.loadChannels(); //Get the channels (data retrieved from API)
                        publish(cachedChannelData); //Send the data that's been collected
                        return null; // Ensure doInBackground returns null as specified by its return type
                    }
    
                    @Override
                    protected void process(List<Map<String, Map<String, programClass>>> chunks) {

                        Map<String, Map<String, programClass>> result = chunks.get(chunks.size() - 1);
                        for (Map.Entry<String, Map<String, programClass>> channelEntry : result.entrySet()) { //For every channel data retrieved from the API, do the following

                            String cname = cm.getChannelName(channelEntry.getKey()); //Get the channel's name
                            rg.displayChannels(cname, channelEntry.getKey()); //Add that channel to the table to display it
                            Map<String, programClass> programs = channelEntry.getValue(); //List of programs in that channel retrieved from the API
                            if(programs != null)
                            { //If there are programs in the channel, hence programs != null
                                for (Map.Entry<String, programClass> programEntry : programs.entrySet()) { //For every program in the channel
                                    programClass program = programEntry.getValue(); //Get a variable containing info about that program
                                    String description = program.getDescription(); // Get the description from the program
                                    JLabel image = program.getDisplayImage(); // Get the image JLabel from the program
                                    String start = program.getStart(); //Get the start time of the program
                                    String end = program.getEnd(); //Get the end time of the program
                                    String name = program.getName(); //Get the name of the program
                                    
                                    // Assuming you have a method to display each program's description and image individually
                                    rg.displayPrograms(description, image, name, start, end); // Display the programs
                                }
                                rg.clearGui(); //Clear the GUI of it's all old displayed data
                            }
                            
                        }
                    }
                };
                sw.execute(); 
            }
        });
    
        dataUpdateTimer.setInitialDelay(0); // Start timer immediately
        dataUpdateTimer.start();
    }

Here’s the order in which I want my application to run:

1. Display a message (JOptionPane)
2. Clear the GUI
3. Collect the data
4. Display the data on screen