[#60] Add a deterministic explicit JPMS descriptor

[peter-lawrey]

Purpose

Repository-owned continuation of #107, stacked on #119 while that PR awaits its required approval. The original #107 commits are retained unchanged in this branch, including Benjamin Marwell's authored commit cdbdc5060cddb1373a86a1575445b68f1b1d08c0.

After #119 merges, retarget this PR to develop and merge it with a merge commit so the original commit graph and attribution remain intact.

What changed relative to #107

• Retains [#60] Add JPMS module descriptor, add Maven IT #107's hand-authored module net.openhft.hashing descriptor, multi-release layout, class-path consumer, and module-path consumer.
• Replaces the JDK [9,) production compilation profile with ModiTect 1.3.0.Final during package.
• A Java 8 Maven build now always adds META-INF/versions/9/module-info.class; descriptor presence no longer depends on the JDK running Maven.
• Retains [#60] Publish a stable JPMS automatic module name #119's Automatic-Module-Name: net.openhft.hashing and packaged-JAR integration test.
• Verifies the packaged descriptor is Java 9 bytecode even when Maven runs on Java 8.
• Strengthens the modular consumer to assert the module is named and non-automatic, exports only net.openhft.hashing, and has a non-static requires jdk.unsupported.
• Skips only the Java 9+ modular consumer when Maven itself runs on Java 8; the ordinary consumer and packaged descriptor checks still run.

Validation

Java 8 build

JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64 mvn -B clean verify

• 14,901 unit tests passed, 12 skipped.
• Both packaged-JAR integration assertions passed.
• Class-path consumer passed; modular consumer was correctly skipped due to the Java 8 runtime.
• Javadocs and licence check passed.

Canonical Java 8-built JAR SHA-256: f629250a02248de8138084e65feac897710fd55d6f0630a397ae6599b1c319ab.

Exact Java 8-built JAR

• Java 8 class-path consumer: passed.
• Java 25 class-path consumer: passed (with the expected terminal-deprecation warning for sun.misc.Unsafe).
• Java 25 module-path consumer: passed and observed explicit module net.openhft.hashing.
• jar --validate: passed.
• jar --describe-module --release 9: exports net.openhft.hashing; requires mandated java.base and jdk.unsupported.

Java 25 build

JAVA_HOME=/usr/lib/jvm/java-25-openjdk-amd64 mvn -B clean verify

• Both 14,901-test executions passed.
• Both packaged-JAR assertions passed.
• Both class-path and explicit-module Invoker consumers passed.
• Javadocs and licence check passed.

Authorship and line-survival audit

• PR [#60] Add JPMS module descriptor, add Maven IT #107's remote head remains 0bfbe9692e9b4c5d937e64f6569815c4c0d0d78f.
• Benjamin Marwell's commit remains exactly cdbdc5060cddb1373a86a1575445b68f1b1d08c0, with author Benjamin Marwell <bmarwell@apache.org> and GitHub author @bmarwell.
• Both commits are unchanged ancestors of this branch through merge commit b84125e0e04efd09b9ffbcec5e2537f169f4645f.
• Across the final [#60] Add a deterministic explicit JPMS descriptor #122 + [#60] Complete JPMS runtime compatibility through Java 25 #123 stack, 345 of the 372 lines added by [#60] Add JPMS module descriptor, add Maven IT #107 survive unchanged and still blame to Benjamin. The other 27 are the 26 JDK-dependent packaging lines replaced in pom.xml and the one corrected integration-test documentation sentence described below.
• The seven-line production descriptor remains wholly attributed to Benjamin.
• The modular consumer's original 41 lines remain attributed to Benjamin; later descriptor assertions only add lines.
• The original simple consumer (90 lines), its POM (42), its Invoker properties (2), the modular consumer POM (42), modular module-info.java (9), settings (6), and the original modular Invoker properties (2) remain attributed to Benjamin.
• Of [#60] Add JPMS module descriptor, add Maven IT #107's pom.xml additions, the multi-release manifest configuration and Maven Invoker integration remain attributed to Benjamin (39 surviving lines).
• The replaced pom.xml lines are specifically the global release property, JDK-conditional compile-java9 execution, and bundle Include-Resource wiring. Those lines made descriptor presence depend on the Maven JDK and therefore had to be replaced by the deterministic ModiTect mechanism.
• Stage 3 replaces one sentence in [#60] Add JPMS module descriptor, add Maven IT #107's integration-test README because it stated that sun.nio.ch could not be accessed, while the preserved direct-buffer fast path deliberately accesses it through a documented --add-exports option. All other original README lines retain Benjamin's attribution.
• No commit introduced by this continuation contains a Claude or Anthropic authorship trailer or attribution. Pre-existing shared base history is unchanged.
• git diff --check passed.

Scope

Part of #60, Stage 2. This establishes deterministic explicit-module packaging. Direct-buffer/internal-API hardening and the broader Java 25 runtime-path matrix belong to Stage 3.

[peter-lawrey]

@bmarwell GitHub cannot add you as a formal requested reviewer because it reports that review requests are limited to repository collaborators, but your review is warmly invited. This continuation retains your original commit and the full #107 head unchanged in its ancestry.

[bmarwell]

It is totally fine as a start