RFR: 8351996: Behavioral updates for ClassValue::remove [v12]

Chen Liang liach at openjdk.org
Fri May 2 15:17:25 UTC 2025


> The recent patch #23866 makes calling `ClassValue::remove()` from `ClassValue::computeValue()` end up in infinite loops while fixing the stale value risk from the method.
> 
> The proposed fix is to preserve the stale value risk fix, and update the remove-from-compute behavior from the original designated no-op behavior to throwing an exception, as the original behavior conflicts with the stale value fix.
> 
> The implementation track the owner thread in promises (accessed in locked section); as a result, we can fail-fast on recursive removals from `computeValue`. I did not choose to use `ThreadTracker` as it is designed for single tracker and multiple threads, while this case here sees often just one thread, and the threads outlive the promise objects.
> 
> Also updated the API specs for `remove` to more concisely describe the memory effects. Please review the associated CSR as well.

Chen Liang has updated the pull request incrementally with one additional commit since the last revision:

  Update src/java.base/share/classes/java/lang/ClassValue.java
  
  Co-authored-by: Shaojin Wen <shaojin.wensj at alibaba-inc.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/24043/files
  - new: https://git.openjdk.org/jdk/pull/24043/files/2292212b..3d68f09a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24043&range=11
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24043&range=10-11

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/24043.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24043/head:pull/24043

PR: https://git.openjdk.org/jdk/pull/24043


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