RFR: 6507038: Memory Leak in JTree / BasicTreeUI [v8]

[Alexey Ivanov]

On Thu, 1 Feb 2024 03:16:27 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

>> When using a TreeCellRenterer which creates new components in getTreeCellRendererComponent() in a JTree that is not visible, changes to the nodes cause a memory leak.
>> When a node is changed, the Method getNodeDimensions() is called to calculate the new dimensions for the node. In this method, getTreeCellRendererComponent() is called to obtain the renderer component (what else...) and [this component is added to rendererPane](https://github.com/openjdk/jdk/blob/36f4b34f1953af736706ec67192204727808bc6c/src/java.desktop/share/classes/javax/swing/plaf/basic/BasicTreeUI.java#L3283-L3284). It is not removed from the rendererPane afterwards. 
>> Only when the tree is painted, the paint() method does a removeAll on the rendererPane [in this code](https://github.com/openjdk/jdk/blob/36f4b34f1953af736706ec67192204727808bc6c/src/java.desktop/share/classes/javax/swing/plaf/basic/BasicTreeUI.java#L1500)
>> 
>> FIx is added to remove the components from rendererPane when the JTree UI is changed/uninstalled only when tree is not visible since they are already removed when tree is painted in paint() method..
>
> Prasanta Sadhukhan has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Test updated

Marked as reviewed by aivanov (Reviewer).

src/java.desktop/share/classes/javax/swing/plaf/basic/BasicTreeUI.java line 3285:

> 3283:                     // Remove previously added components to prevent leak
> 3284:                     // and add the current component returned by cellrenderer for
> 3285:                     // painting and other measurements

I think the comment is redundant.

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PR Review: https://git.openjdk.org/jdk/pull/17458#pullrequestreview-1856276349
PR Review Comment: https://git.openjdk.org/jdk/pull/17458#discussion_r1474314841