RFR: 6450193: After the first Serialization, JTableHeader does not uninstall its UI

[Damon Nguyen]

On Thu, 31 Aug 2023 08:02:35 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

> After the first time a JTableHeader is serialized, it no longer will uninstall its UI upon subsequent serializations.
> This happens for classes that use the BasicTableHeaderUI class. Any LAF that extends the BasicTableHeaderUI like SynthTableHeaderUI and WindowsTableHeaderUI will get an NotSerializableException thrown
> 
> Each time an JComponent instance is Serialized, a [counter ](https://github.com/openjdk/jdk/blob/218829e0a2a3ae5599b81733df53557966392033/src/java.desktop/share/classes/javax/swing/JComponent.java#L5644-L5645) for the instance is incremented. It is de-incremented in JComponent's writeObject or a class that implements it the same way, like JButton, JScrollPane etc..
> With JTableHeader it does not deincrement the counter. The uninstall mechanism will not uninstall a UI if the counter is not 0 on the first pass..It is not possible to call JComponent.setWriteObjectCounter in JTableHeader as it is not in the same package so the fix is to remove the writeObject implementation and rely on JComponent writeObject implementation to make sure uninstallation of UI happens and also NotSerializableException does not happen for Synth

Does the copyright year in JTableHeader.java need to be updated to 2023 as well?

test/jdk/javax/swing/JTableHeader/SerializeJTableHeader.java line 39:

> 37: import java.io.ObjectOutputStream;
> 38: 
> 39: public class SerializeJTableHeader implements Runnable{

Suggestion:

public class SerializeJTableHeader implements Runnable {

test/jdk/javax/swing/JTableHeader/SerializeJTableHeader.java line 44:

> 42:         JTableHeader jth = new JTableHeader();
> 43:         try {
> 44:             for(int i = 0; i < 10; i ++){

Suggestion:

            for(int i = 0; i < 10; i++) {

test/jdk/javax/swing/JTableHeader/SerializeJTableHeader.java line 68:

> 66:     }
> 67: 
> 68:     public static void main(String ... args) throws Exception{

Suggestion:

    public static void main(String ... args) throws Exception {

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PR Review: https://git.openjdk.org/jdk/pull/15507#pullrequestreview-1607662850
PR Review Comment: https://git.openjdk.org/jdk/pull/15507#discussion_r1313519001
PR Review Comment: https://git.openjdk.org/jdk/pull/15507#discussion_r1313520520
PR Review Comment: https://git.openjdk.org/jdk/pull/15507#discussion_r1313519686