boxLayout无法共享

Question

有这个Java JFrame类，我想在其中使用boxlayout，但是我收到一条错误，指出java.awt.AWTError: BoxLayout无法共享

这是代码

public class secureChat {

    private JFrame myFrame;

    private int width;
    private int height;

    private JPanel allPanel;
    private JPanel titlePanel;
    private JPanel holdPanel;
    private JPanel serverPanel;
    private JPanel portPanel;
    private JPanel encrypPanel;
    private JPanel decrypPanel;


    public static void main(String[] args) {
        secureChat S = new secureChat();
    }

    public secureChat()
    {
        width = 600;
        height = 480;
        myFrame = new JFrame();
        myFrame.setLocation(450, 200);
        myFrame.setTitle("secure chat");
        myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        myFrame.setSize(width, height);

        allPanel = new JPanel();
        myFrame.add(allPanel);
        allPanel.setLayout(new BoxLayout(allPanel, BoxLayout.Y_AXIS));
        allPanel.setBackground(Color.blue);

        titlePanel = new JPanel();
        allPanel.add(titlePanel);
        titlePanel.setLayout(new BoxLayout(titlePanel, BoxLayout.X_AXIS));

        holdPanel = new JPanel();
        allPanel.add(holdPanel);
        holdPanel.setLayout(new BoxLayout(holdPanel, BoxLayout.X_AXIS));
    }
}

任何帮助都是apreciated