> The AWTEventMulticaster is a tree node with 2 children. This PR proposes > rebalancing that tree after 500 additions to avoid potential > StackOverflowErrors when trying to interact with a large AWTEventMulticaster. > > In the original headful test: > We added 8,000 checkboxes, and when their parent panel was hidden the stack > needed to grow to 24,000 lines. It took 8,000 lines to recursively call > `java.awt.AWTEventMulticaster.componentHidden`, and then 16,000 additional > lines to call two recursive methods to remove a listener: > > java.desktop/java.awt.AWTEventMulticaster.removeInternal() > java.desktop/java.awt.AWTEventMulticaster.remove() > > > With this current PR the max stack size reaches 1,267 instead. (If we > rebalanced at EVERY addition, then that same scenario would reach a max stack > size of 71.) > > JDK-8342782 included a headful test case, but I think the main problem it > demonstrated can be represented by the headless test case attached to this PR. > > Depending on how this PR is received I may submit a separate ticket & PR to > modify AquaButtonUI so it doesn't always attach an AncestorListener. (That > is: if my GUI includes 8,000 checkboxes then I don't need 8,000 > AncestorListeners.) But JDK-8342782's test case is currently written in a way > that should reproduce across all L&F's, so that can be discussed separately.
Jeremy has updated the pull request incrementally with five additional commits since the last revision: - 8342782: move comments re implementation details inside method Also avoid restating constant, instead only refer to it as "threshold" This is in response to: https://github.com/openjdk/jdk/pull/21962#discussion_r1855148909 - 8342782: adding an empty line representing EOF This is in response to: https://github.com/openjdk/jdk/pull/21962#discussion_r1871348260 - 8342782: changing "/2" to " / 2" This is in response to: https://github.com/openjdk/jdk/pull/21962#discussion_r1871376542 - 8342782: change threshold from 500 to 100 This is in response to: https://github.com/openjdk/jdk/pull/21962#discussion_r1855398578 - 8342782: convert value (500) to named constant This is in response to: https://github.com/openjdk/jdk/pull/21962#discussion_r1855397860 ------------- Changes: - all: https://git.openjdk.org/jdk/pull/21962/files - new: https://git.openjdk.org/jdk/pull/21962/files/ed6a585a..f2212092 Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=21962&range=05 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21962&range=04-05 Stats: 14 lines in 2 files changed: 6 ins; 5 del; 3 mod Patch: https://git.openjdk.org/jdk/pull/21962.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/21962/head:pull/21962 PR: https://git.openjdk.org/jdk/pull/21962
