@Override
public void actionPerformed(ActionEvent e) {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(600,600);
    frame.setVisible(true);
    frame.setLayout(new BorderLayout(25,0));

    int r;
    int g;
    int b;
    Random rand = new Random();

    r = rand.nextInt(255);
    g = rand.nextInt(255);
    b = rand.nextInt(255);
    Color c1 = new Color(r,g,b);
    Color c2 = new Color(r,g,b);
    Color c3 = new Color(r,g,b);

    JPanel panel = new JPanel();
    panel.setBackground(c1);
    panel.setPreferredSize(new Dimension(200,200));
    frame.add(panel, BorderLayout.EAST);

    JPanel panel1 = new JPanel();
    panel.setBackground(Color.BLACK);
    panel1.setPreferredSize(new Dimension(200,200));
    frame.add(panel1, BorderLayout.WEST);

    JPanel panel2 = new JPanel();
    panel.setBackground(Color.gray);
    panel2.setPreferredSize(new Dimension(200,200));
    frame.add(panel2, BorderLayout.CENTER);
}

}

When this action is performed, it only shows one of the colors in a separate window, when I wanted all three of the colors to be shown, side by side, and fill up the entire window with the three panels.