Claude
1d0cd8b36e
Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01CifR2BE7PBvRy5hT8TS9oz
35 lines
1.9 KiB
Markdown
35 lines
1.9 KiB
Markdown
# streaming-huge-json
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Companion code for the rewritten post
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[Jackson Streaming API and JsonNode (Jackson 3)](https://ankurm.com/jackson-streaming-api-jsonnode/).
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A self-contained Maven module (not part of the root build). It generates a 1 GiB JSON array,
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then counts the `ERROR` records four ways under fixed `-Xmx` limits.
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```
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Jackson 3.2.4 (tools.jackson.core:jackson-databind, GA on Maven Central 2026-10-18)
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JDK Temurin 25.0.5 (LTS)
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```
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| Class | What it shows |
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|---|---|
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| [`GenerateHugeJson`](src/main/java/com/ankurm/jackson3/streaminghuge/GenerateHugeJson.java) | Writing 1 GiB with `JsonGenerator` under `-Xmx64m` |
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| [`Scan`](src/main/java/com/ankurm/jackson3/streaminghuge/Scan.java) | `stream`, `hybrid`, `tree`, `bind` (and the broken `hybrid-naive`) |
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| [`NestedTrap`](src/main/java/com/ankurm/jackson3/streaminghuge/NestedTrap.java) | The flat-object loop breaking on nested JSON; `skipChildren()` fix |
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| [`TruncatedFile`](src/main/java/com/ankurm/jackson3/streaminghuge/TruncatedFile.java) | What a cut-off file does to streaming vs tree |
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| [`ReadLimits`](src/main/java/com/ankurm/jackson3/streaminghuge/ReadLimits.java) | Default `StreamReadConstraints` values |
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```bash
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cd streaming-huge-json
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./scripts/run-all.sh --quick # small demos only
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./scripts/run-all.sh # also generates target/huge.json (1 GiB, git-ignored) and runs the ladder
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```
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Captured output is in [`output/`](output). Memory figures are from one run on a 2-CPU, 8 GB
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container; `peakUsed` is sampled `total - free` heap and includes garbage not yet collected.
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Timings vary between runs; the pass/fail pattern per `-Xmx` is the stable part.
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Note on `output/bench.txt`: the `tree -Xmx= 6144 MB KILLED` line comes from a separate manual run
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(the first ladder run printed a blank line for it because the OS killed the JVM, exit 137);
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`scripts/bench.sh` now records that case itself.
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