On Wed, 24 Jan 2024 05:35:42 GMT, Prasanta Sadhukhan <psadhuk...@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: > > Retain last component in rendererPane. Testcase added Changes requested by aivanov (Reviewer). src/java.desktop/share/classes/javax/swing/plaf/basic/BasicTreeUI.java line 3285: > 3283: for (int i = 0; i < > rendererPane.getComponentCount(); i++) { > 3284: rendererPane.remove(i); > 3285: } rendererPane.removeAll()? Suggestion: rendererPane.removeAll(); test/jdk/javax/swing/plaf/basic/BasicTreeUI/TreeCellRendererLeakTest.java line 62: > 60: } > 61: > 62: public void finalize( ) { The `finalize` method is deprecated. Can't we use `Reference` API for this purpose? Store a list of [`PhantomReference<JLabel>`](https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/ref/PhantomReference.html). The size of the list is the number of `JLabel` objects created. Once you receive a reference via the [`ReferenceQueue`](https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/ref/ReferenceQueue.html), remove it from the list. test/jdk/javax/swing/plaf/basic/BasicTreeUI/TreeCellRendererLeakTest.java line 90: > 88: } > 89: > 90: return label; Here, before returning the `label` object, create a `PhantomReference` and add it to a list of references. test/jdk/javax/swing/plaf/basic/BasicTreeUI/TreeCellRendererLeakTest.java line 101: > 99: runChanges( ); > 100: } > 101: }); This could be a method reference: Suggestion: Thread updateThread = new Thread(this::runChanges); test/jdk/javax/swing/plaf/basic/BasicTreeUI/TreeCellRendererLeakTest.java line 108: > 106: runInfo( ); > 107: } > 108: }); Suggestion: Thread infoThread = new Thread(this::runInfo); test/jdk/javax/swing/plaf/basic/BasicTreeUI/TreeCellRendererLeakTest.java line 150: > 148: while (!done) { > 149: Thread.sleep(100); > 150: } Can't we use [`CountDownLatch`](https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/util/concurrent/CountDownLatch.html) instead of a boolean flag and busy-waiting? test/jdk/javax/swing/plaf/basic/BasicTreeUI/TreeCellRendererLeakTest.java line 183: > 181: } catch (Exception ex) { > 182: ex.printStackTrace(); > 183: } You may want to handle `InterruptedException` by exiting from the thread… test/jdk/javax/swing/plaf/basic/BasicTreeUI/TreeCellRendererLeakTest.java line 191: > 189: public void runInfo( ) { > 190: long time = System.currentTimeMillis(); > 191: long initialCnt = smCount; Access to `smCount` or a list of references need to be synchronised. ------------- PR Review: https://git.openjdk.org/jdk/pull/17458#pullrequestreview-1842292468 PR Review Comment: https://git.openjdk.org/jdk/pull/17458#discussion_r1465491797 PR Review Comment: https://git.openjdk.org/jdk/pull/17458#discussion_r1465498201 PR Review Comment: https://git.openjdk.org/jdk/pull/17458#discussion_r1465504463 PR Review Comment: https://git.openjdk.org/jdk/pull/17458#discussion_r1465505654 PR Review Comment: https://git.openjdk.org/jdk/pull/17458#discussion_r1465506021 PR Review Comment: https://git.openjdk.org/jdk/pull/17458#discussion_r1465499294 PR Review Comment: https://git.openjdk.org/jdk/pull/17458#discussion_r1465507807 PR Review Comment: https://git.openjdk.org/jdk/pull/17458#discussion_r1465501423
