RFR: 4337898: Serializing DefaultTableCellRenderer changes colors [v2]

[Alexander Zvegintsev]

On Mon, 1 Dec 2025 06:49:27 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

>> When a `JTable `using any objects of type `DefaultTableCellRenderer`, or subclasses, is serialized, 
>> the colors used to render cells in the JTable subsequent to the call to `writeObject()`
>>  are forced to the default colors for `DefaultTableCellRenderer`'s immediate base class, JLabel, causing the colors
>> defined in the JTable (typically black on white) to be ignored.
>> 
>> The problem seems to stem from a call to
>> `installUI `in the `writeObject()` method of `JLabel`, `DefaultTableCellRenderer`'s base class.
>>  This causes the `setForeground` and `setBackground` methods to be invoked with specific colors, which turn out to be JLabel's defaults.
>> Invoking these methods subsequently with parameters of null restores normal operation same as is explicitly done in `DefaultTableCellRenderer.updateUI()`
>> https://github.com/openjdk/jdk/blob/195b36f90b789b64f4a0fc867c620935d609a455/src/java.desktop/share/classes/javax/swing/table/DefaultTableCellRenderer.java#L159-L162
>> 
>> CI run is ok..
>
> Prasanta Sadhukhan has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Automate test

test/jdk/javax/swing/DefaultTableCellRenderer/DefRendererSerialize.java line 72:

> 70:                 table.setDefaultRenderer(table.getColumnClass(1), tcr);
> 71: 
> 72:                 // If this try block is removed, table text remains black on white.

This comment is too far away from the try-catch block after the test update.

test/jdk/javax/swing/DefaultTableCellRenderer/DefRendererSerialize.java line 101:

> 99:                     System.out.println("deserialized renderer fg " + fg + " bg " + bg);
> 100:                     if (!(fg == destcr.getForeground()) || !(bg == destcr.getBackground())) {
> 101:                         throw new RuntimeException("Desrialized foreground and background color not same");

Suggestion:

                        throw new RuntimeException("Deserialized foreground and background color not same");

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

PR Review Comment: https://git.openjdk.org/jdk/pull/28549#discussion_r2575913375
PR Review Comment: https://git.openjdk.org/jdk/pull/28549#discussion_r2575910014