hashmap-concurrenthashmap: companion code for the HashMap vs ConcurrentHashMap interview guide

Adds JMH put/get throughput benchmarks (synchronizedMap vs ConcurrentHashMap,
swept at 1/2/4/8 threads), a computeIfAbsent recursion trap demo (CHM tolerates
recursion into a different key but throws IllegalStateException on the same
key; plain HashMap throws ConcurrentModificationException even single-threaded),
and a null-handling demo (CHM rejects null keys/values on put() and null keys
on get() too). 7/7 JUnit tests pass; all output/ transcripts captured from
real runs.

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01FhzLY5p6okFva3qsnsRyvM
This commit is contained in:
2026-09-30 09:29:06 +00:00
co-authored by Claude Sonnet 5
parent af615cc17c
commit 4a74153d87
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Test set: com.ankurm.hashmapconcurrenthashmap.MapClaimsTest
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Tests run: 7, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.101 s -- in com.ankurm.hashmapconcurrenthashmap.MapClaimsTest