How can my program randomly press a button?

I'm trying to make a game where the button would light up and the user would have to press the button in a given time.

Currently, my program has 12 buttons that do something. I'm trying to make it so that these buttons are randomly called by the program. So far, I just have these for 12 buttons that just change the text when pressed by the user.

Now I need a way of making it so that they are randomly pressed the program itself and not the user. Any idea's on how this is done in java?

// **** Panels for buttons ****
        JPanel panelButtons = new JPanel();                         // making the panel for the buttons
        panelButtons.setLayout(new GridLayout(3, 4));               // setting the layout of the buttons to 3x4 as shown above

        b1 = new JButton(" ⃝");                                     // creating button and setting its default text
        b1.setFont(fontText);                                       // setting the font
        b1.addActionListener(new ActionListener(){                  // action listener to do something when pressed
            public void actionPerformed(ActionEvent e) {
                    sendMessage(user + "1" );                       // sends the name of the user that pressed the button and which button
                    String field1 = b1.getText();                   // gets the text from the button and stores it in a String
                    if(field1 == " ⃝"){                             // checks if the string is equal to an empty circle
                        b1.setText("⬤");                            // if true then change to a full circle
                    }
                    else if (field1 == "⬤"){                        // opposite of the above if statement
                        b1.setText(" ⃝");
                    }   
            }
        }); 
        panelButtons.add(b1);                                       // adding the button to the panel

        b2 = new JButton(" ⃝");                                     // creating button and setting its default text
        b2.setFont(fontText);                                       // setting the font
        b2.addActionListener(new ActionListener(){                  // action listener to do something when pressed
            public void actionPerformed(ActionEvent e) {            
                    sendMessage(user + "2" );                       // sends the name of the user that pressed the button and which button
                    String field2 = b2.getText();                   // gets the text from the button and stores it in a String
                    if(field2 == " ⃝"){                             // checks if the string is equal to an empty circle
                        b2.setText("⬤");                            // if true then change to a full circle
                    }
                    else if (field2 == "⬤"){                        // opposite of the above if statement
                        b2.setText(" ⃝");
                    }   
            }
        });
        panelButtons.add(b2);                                       // adding the button to the panel