RFR: 4938801: The popup does not go when the component is removed [v6]

[Alexey Ivanov]

On Wed, 30 Jul 2025 09:53:13 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

>>>> You can serialize a lambda expression if its target type and its captured arguments are serializable
>> 
>> I think that means `propListener` is NOT going to serialize, because `PropertyChangeListener` isn't `Serializable`. I'm unfamiliar with these details; I found this link helpful: https://www.baeldung.com/java-serialize-lambda
>> 
>> Alternatively: if we put `propListener` in BasicPopupMenuUI: then I think serialization will be less of an issue. `JComponent#ui` is transient, so we don't try to serialize it (and all of its other listeners). This way the JPopupMenu will come out on the other side of deserialization using whatever the L&F is in that setup. This feels good-ish to me.
>> 
>> (I'm assuming most L&F's extend BasicPopupMenuUI?)
>> 
>> This is all just an idea/suggestion; as long as the deserialized JPopupMenu behaves like the original JPopupMenu I think that should be fine.
>
> Yes, it seems deserialized JPopupMenu fails hiding the popup menu owing to `propListener` not getting serialized.
> 
> Tried with modified testcase of yours and fixed in latest PR
> 
> 
> import java.awt.*;
> import java.awt.event.*;
> import javax.swing.*;
> import java.beans.PropertyChangeListener;
> import java.io.*;
> 
> public class JPopupMenuSerializationTest {
> 
>     public static class MyThread implements Runnable {
>         static Container box;
>         static Component invo;
> 
>         public MyThread(Container cont, Component comp) {
>             this.invo = comp;
>             this.box = cont;
>         }
> 
>         public void run() {
>             System.out.println("Starting 3 second countdown...");
>             try{
>                 Thread.currentThread().sleep(3000);
>             } catch (Exception e) {}
>             System.out.println("Removing popup invoker from the container.");
>             box.remove(invo);
>             box.repaint();
>         }
>     }
> 
>     public static void main(String[] args) throws Exception {
>         JPopupMenuSerializationTest test = new JPopupMenuSerializationTest();
>         test.testSerialization();
>     }
> 
>     public void testSerialization() throws Exception {
>         JPopupMenu popupMenu = new JPopupMenu();
>         byte[] data = serialize(popupMenu);
>         JPopupMenu copy = deserialize(data);
> 
>         test(copy);
>     }
> 
>     private void test(JPopupMenu jpm) {
>         JFrame frame = new JFrame("My frame");
>         final Container pane = frame.getContentPane();
>         pane.setLayout(new BorderLayout());
>         pane.add(new JTextField("", 20), BorderLayout.NORTH);
>         JButton btn = new JButton("Exit");
>         final Thread[] thr = new Thread[] { null };
>         btn.setAction(new AbstractAction() {
>             public void actionPerformed(ActionEvent ev) {
>                 System.exit(0);
>             }
>         });
>         btn.setText("Exit");
>         pane.add(btn, BorderLayout.SOUTH);
>         final JLabel label = new JLabel("Click here to invoke popup");
>         label.addMouseListener(new MouseAdapter() {
>             public void mouseReleased(MouseEvent e) {
>                 jpm.add("One");
>                 jpm.add("Two");
>                 jpm.add("Three");
>                 jpm.show(label,
>                         label.getLocationOnScreen().x,
>                         label.getLocationOnScreen().y);
>             }
> 
>             public void mousePressed(MouseEvent e) {
>                 Thread thr = new Thread(new MyThread(pane, label));
>                 thr.st...

Do we even care about serialisation as much?

What would be the use case?

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/26407#discussion_r2242601894