RFR: 8262518: SwingNode.setContent does not close previous content, resulting in memory leak [v3]

[Andy Goryachev]

On Wed, 23 Aug 2023 13:21:00 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

>> Issue is when setting the content of a SwingNode, the old content is not garbage collected owing to the fact
>> JLightweightFrame is never being released by SwingNodeDisposer
>> 
>> The SwingNodeDisposer holds an hard pointer to the JLightweightFrame that prevents its collection
>> 
>> Modified `SwingNode.setContentImpl`  function to use a WeakReference to properly release the memory.
>
> Prasanta Sadhukhan has updated the pull request incrementally with one additional commit since the last revision:
> 
>   DisposerRecord leak fix

modules/javafx.swing/src/main/java/com/sun/javafx/embed/swing/Disposer.java line 92:

> 90:     }
> 91: 
> 92:     public static void removeRecord(WeakReference ref) {

may be add a javadoc comment?

modules/javafx.swing/src/main/java/javafx/embed/swing/SwingNode.java line 368:

> 366:     private void setContentImpl(JComponent content) {
> 367:         if (lwFrame != null) {
> 368:             rec.dispose();

is it possible for `rec` to be null at this point?
would it make sense to rewrite this code block as

if(rec != null) {
  rec.dispose();
  rec = null;
}
if(disposeRecRef != null) {
  Disposer.removeRecord(...)
  disposerRecRef = null;
}
if(lwFrame != null) {
 lsFrame = null;
}

?

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

PR Review Comment: https://git.openjdk.org/jfx/pull/1219#discussion_r1303153898
PR Review Comment: https://git.openjdk.org/jfx/pull/1219#discussion_r1303151756