Java idempotent retries: no reply does not mean no effect

01 / QUESTION

Seven loopback HTTP fault cases explain idempotency keys, concurrent admission, payload conflicts and process-crash gaps.

METHOD

Freeze source and protocol, execute local comparisons, archive raw records and independently recompute with hash checks.

RESULT

Seven loopback HTTP cases: lost replies and 12 concurrent duplicates execute once within a process; restart and crash gaps still duplicate effects.

OBSERVATIONS

Seven loopback HTTP cases: lost replies and 12 concurrent duplicates execute once within a process; restart and crash gaps still duplicate effects.

CONCLUSION

Distinguish a lost reply from an unknown effect; reproduce concurrent deduplication and crash gaps.

LIMITATIONS

Volatile deduplication only: no database transaction, distributed guarantee, live model call or exactly-once claim.

REPRODUCE

The article supplies a pinned commit, locked environment, separate output directory and audit command.

1. Tutorials

   Java idempotent retries: no reply does not mean no effect

   Seven loopback HTTP fault cases explain idempotency keys, concurrent admission, payload conflicts and process-crash gaps.

   2026-10-0911 MINPublished
2. PROJECT / 002

   Java LLM Practice

   Reproducible Java conversation, retry and persistence boundaries, alongside attention, cache-cost and quantization-error experiments.

   Building
3. Engineering cases

   Durable Java turns: what survives a process crash?

   Checksummed append records, 142 truncated prefixes and three halted JVMs distinguish local recovery from remote exactly-once execution.

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