JLabel不显示在JFrame上，而仅显示在JOptionPane上

Question

I'm receiving a buffered image as byte[] but when I update the icon of JLabel nothing changes on JFrame even revalidating both JFrame and JLabel. Instead, when I try to show the JLabel in a JOptionPane it works fine. I don't understand why. Here is the code :

public class ScreenMonitorServer extends JFrame
{
private String botIPAddress;
private ServerSocket serverSocket;
private Socket botSocket;
private JLabel screen;

public ScreenMonitorServer(String botIPAddress)
{
    super(botIPAddress+" - Screen Monitor");
    this.botIPAddress=botIPAddress; 
    setLayout(new FlowLayout());
    screen=new JLabel();
    add(screen);
    setVisible(true);
    try
    {
        serverSocket=new ServerSocket(54323);
        do
            botSocket=serverSocket.accept();
        while(!botSocket.getInetAddress().getHostAddress().equals(botIPAddress));
        ObjectInputStream ois=new ObjectInputStream(botSocket.getInputStream());
        while(true)
        {
            BufferedImage image;
            InputStream in=new ByteArrayInputStream((byte[])ois.readObject());
            BufferedImage bImageFromConvert=ImageIO.read(in);
            ImageIcon screenImage=new ImageIcon(bImageFromConvert);
            setSize(bImageFromConvert.getWidth(),bImageFromConvert.getHeight());
            screen.setIcon(screenImage); //black screen
            JOptionPane.showMessageDialog(null,screen);  //works fine
        }
    }   
    catch(IOException exc)
    {
        exc.printStackTrace();
    }
    catch(ClassNotFoundException exc)
    {

    }
  }
}

Answer 1

All Swing component can have just one parent component, so when you call JOptionPane.showMessageDialog(null,screen); you ovveride previous parent and your JLabel remove from ScreenMonitorServer .

Read here .

You need to use two instance of JLabel in that case.

Answer 2

I resolved by placing the infinite loop in an other thread. Thanks for the help.