asmhatreandClaude Sonnet 5.5
0457cf4bfb
Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_017ic4b4VQVEJWetTT1dYzyJ
33 lines
1.5 KiB
Markdown
33 lines
1.5 KiB
Markdown
# lru-cache
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Runnable companion for the ankurm.com article
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[LRU Cache in Java: LinkedHashMap, HashMap + Doubly Linked List and a Thread-Safe Version](https://ankurm.com/lru-cache-in-java/).
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Three LRU caches, three thread-safe variants, a Caffeine reference, a deliberately broken
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`ReadWriteLock` version, correctness and stress tests, and a short JMH comparison.
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| Component | Version | Verified against |
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| JDK | 25.0.5+8 (Temurin, LTS) | `java -version` |
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| JUnit | 6.1.3 | `maven-metadata.xml` on Maven Central |
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| Caffeine | 3.3.1 | `maven-metadata.xml`; GitHub release page lists it as Latest |
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| JMH | 1.37 | `maven-metadata.xml` |
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```bash
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export JAVA_HOME=/path/to/jdk-25 && export PATH="$JAVA_HOME/bin:$PATH"
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cd lru-cache
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mvn test # 43 tests; rewrites output/01-08
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./scripts/run-all.sh # also regenerates output/09 (broken-lock demo) and 10 (JMH)
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```
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| Source | What it is |
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| `LinkedHashMapLruCache` | `LinkedHashMap(accessOrder=true)` + `removeEldestEntry` |
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| `HashMapLruCache` | `HashMap` + hand-rolled doubly linked list with sentinel head/tail |
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| `SynchronizedLruCache`, `ReentrantLockLruCache` | one coarse lock around variant 2 |
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| `StripedLruCache` | N independent segments, LRU per segment (not global) |
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| `BrokenReadWriteLockLruCache`, `BrokenLockDemo` | the tempting wrong answer, and what it does |
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| `CaffeineLru`, `bench/LruBenchmark` | production reference and the JMH harness |
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`output/09` and `output/10` are measurements from a shared 2-vCPU sandbox: indicative, not asserted.
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