Fix O(n²) performance in WrapperProperties$OrderedProperties#12542
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Fix O(n²) performance in WrapperProperties$OrderedProperties#12542gnodet wants to merge 1 commit into
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Replace CopyOnWriteArrayList with LinkedHashMap for key ordering in OrderedProperties. CopyOnWriteArrayList.contains() is O(n), making every put() call O(n) and putAll() O(n²). LinkedHashMap provides O(1) put/contains/remove while preserving insertion order. This also simplifies the implementation: LinkedHashMap's entrySet(), keySet(), and values() already provide ordered views, eliminating the need for custom AbstractSet inner classes. JFR profiling shows WrapperProperties consuming ~13% of CPU during 'mvn validate' on large projects (676 modules), primarily from the O(n²) putAll path triggered by keySet()/entrySet()/values() which each create a new OrderedProperties copy. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Summary
CopyOnWriteArrayListwithLinkedHashMapfor key ordering inOrderedPropertiesCopyOnWriteArrayList.contains()is O(n), making everyput()call O(n) andputAll()O(n²)LinkedHashMapprovides O(1) put/contains/remove while preserving insertion orderKeySet/EntrySetinner classes —LinkedHashMapviews handle this nativelyJFR profiling shows
WrapperPropertiesconsuming ~13% of CPU duringmvn validateon Apache Camel (676 modules), primarily from the O(n²)putAllpath triggered bykeySet()/entrySet()/values()which each create a newOrderedPropertiescopy.Test plan
mvn test -pl compat/maven-model— all tests passmvn test -pl impl/maven-impl— 466 tests passmvn test -pl compat/maven-model-builder— 166 tests pass🤖 Generated with Claude Code