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Add jextract module: SQLite bindings generated with jextract, FFM arenas, C strings, out-parameters, errors, upcalls, and a JMH comparison with JNI

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jextract-25 early-access build (25-jextract+2-4) on JDK 25.0.5+8 against SQLite 3.45.1: 25 functions and 13 constants
generated into 4 committed files (the whole header would be 83 files), a small Db wrapper, the four arena kinds
used wrongly on purpose, ADDRESS vs C_POINTER zero-length vs unbounded segments and the SIGSEGV from getString
on a NULL pointer, sqlite3_open out-parameter, return codes to exceptions, a sqlite3_exec upcall and the VM exit
when it throws, the JDK 25 native-access warning and --illegal-native-access=deny, library loading failures,
and a JMH benchmark of FFM vs hand-written JNI vs plain Java (indicative only: shared 2-CPU machine).

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_017ic4b6Kg9RWSTJzyz6KP9X
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asmhatre
2026-10-30 16:36:09 +00:00
co-authored by Claude Sonnet 5.5
parent 41101bea40
commit ecceaa8b32
37 changed files with 2867 additions and 0 deletions
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@@ -74,6 +74,7 @@ These modules keep only sources, a `run.sh` and their transcripts (`output/`). T
| [`structured-concurrency-final/`](structured-concurrency-final) | Structured Concurrency Is Final in JDK 28 (JEP 543): From Preview to Production | the thread leak of `ExecutorService` and its fix, every built-in `Joiner`, structure violations, timeouts, a custom joiner, JSON thread dumps, scoped values, `javap` diffs of the API on JDK 25, 26, 27 and 28-ea, the compiler output for six pieces of 25/26-era code, and the preview class-file trap between 27 and 28 |
| [`kdf/`](kdf) | Key Derivation Function API in Java (JEP 510): HKDF Explained with Real Examples | `javax.crypto.KDF` final in JDK 25, `HKDF-SHA256/384/512`, extract vs expand, RFC 5869 vectors asserted, a hand-written HKDF and 300 generated cases compared with Python `cryptography` and `openssl kdf`, per-tenant keys with length-prefixed `info`, and the mistakes reproduced (same `info`, ambiguous concatenation, PIN through HKDF vs PBKDF2) |
| [`classfile-api/`](classfile-api) | The Java ClassFile API (JEP 484): Read, Generate and Transform Bytecode Without ASM | `java.lang.classfile` final since JDK 24: `parse` and `ClassModel` traversal, `ClassFile.build` with `defineClass` and `defineHiddenClass`, five deliberately broken classes (including swapped exception-table labels that `verify()` misses), timing inserted with `ClassTransform`/`MethodTransform`/`CodeTransform`, the same three jobs in ASM 9.11.1 asserted equal, class-file version limits, a JDK 24/25/26 API diff and a look inside `spring-core` 7.0.10 |
| [`jextract/`](jextract) | Calling C from Java with jextract and the FFM API: A Real Library, No JNI | jextract (early-access build for JDK 25) bindings for SQLite 3.45.1, the four arena kinds used wrongly on purpose, `C_POINTER` vs `ADDRESS` (zero-length pointers, and a `SIGSEGV` from `getString` on a NULL pointer), `sqlite3_open` out-parameter, return codes to exceptions, a `sqlite3_exec` upcall (and the JVM exit when it throws), the JDK 25 native-access warning and `--illegal-native-access=deny`, and a JMH comparison of FFM, hand-written JNI and plain Java |
## Captured output (`docs/output/`)