Fix ConcurrentModificationException on mass Ant project open.#7989
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mbien merged 1 commit intoapache:masterfrom Dec 1, 2024
Merged
Fix ConcurrentModificationException on mass Ant project open.#7989mbien merged 1 commit intoapache:masterfrom
mbien merged 1 commit intoapache:masterfrom
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Evaluators synchronize their inner workings on a per-instance basis. The static cache however is shared between instances and should use a sharable collection. ConcurrentHashMap is probably the best choice here, since the potentially long running computeIfAbsent would only lock the item, not the map.
mbien
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Nov 25, 2024
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| /** | ||
| * cache shared between Evaluator instances. | ||
| */ | ||
| private static final Map<String, String> limitModulesCache = new ConcurrentHashMap<>(); | ||
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| private static String getLimitModules(String javacRelease) { | ||
| return limitModulesCache.computeIfAbsent(javacRelease, release -> { |
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on second thought: this probably could be a plain old synchronized map? The keys are javac release versions, so it won't use the per-item lock feature of the CMH very often.
matthiasblaesing
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Nov 29, 2024
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matthiasblaesing
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To me this looks sane as is. If I'm not mistaken, the map should quickly become read-only (all values are cached). I would expect this to be more performant on a ConcurrentHashMap. But I think it does not mapper to much.
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Evaluators synchronize their inner workings on a per-instance basis. The static cache however is shared between instances and should use a sharable collection.
ConcurrentHashMapis probably the best choice here, since the potentially long runningcomputeIfAbsentwould only lock the item, not the map. (although in practice it probably doesn't have enough keys to leverage this feature)Exception during NB startup while it is trying to open ~100 NB modules
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