RELEASE_NOTES.adoc

Release Notes

Table of Contents

• 1. Upgrade highlights
• 2. Unreleased updates since Java-Thread-Affinity-2026.2
• 3. Release summary
• 4. Notes for maintainers

This document summarises tagged Java-Thread-Affinity releases from 2020-01-01 onwards, using the annotated Git tag dates and the commit history available on 2026-04-28. Both legacy affinity- tags and Java-Thread-Affinity- tags are included where they fall in that window.

The emphasis is on user-visible behaviour, compatibility, dependency alignment, and operational impact. Early-access releases are marked with ea in the version name. The type marker uses ASCII rather than emoji to stay within the repository character-set policy:

• [F] Functional - API, runtime behaviour, operating-system support, diagnostics, or lock semantics changed.

• [N] Non-functional - release alignment, dependency alignment, build, documentation, test, or metadata changes only.

1. Upgrade highlights

• The latest tagged release in this window is Java-Thread-Affinity-2026.2. It is primarily a Maven/BOM alignment release over 2026.1.

• There are unreleased branch updates after Java-Thread-Affinity-2026.2. The main develop/ea line only contains the post-release snapshot reset; separate feature and documentation branches contain JUnit 5 migration work and documentation clean-up.

• The main functional upgrade path after 3.23.x is the 3.26/3.27/2026.x line. That line improves modern Java support, CPU id validation, hyper-thread sibling handling for acquireCore(), diagnostics, and test coverage.

• AffinitySupport was removed after the 3.23.x line. Applications still importing net.openhft.affinity.AffinitySupport should call the corresponding methods on net.openhft.affinity.Affinity before upgrading to 3.26.x or later.

• Custom LockChecker implementations should implement obtainLock(int id, int id2, String metaInfo). The older one-id overload was deprecated in the 3.27ea1 line so a physical core can reserve more than one logical CPU when hyper-threading is present.

• Locking behaviour became safer across the 2020-2022 releases. Notable changes include releasing an AffinityLock without resetting the current thread, avoiding release of locks held by other processes, improving lock metadata under contention, handling OverlappingFileLockException, and handling interrupted acquireLock() calls.

• Platform and topology support broadened over the same period. The releases added or improved ppc64le support, ARM 32-bit and 64-bit rdtsc, more-than-64-core reserved masks, offline CPU handling, unusual /proc/cpuinfo handling, no-affinity environments, and Windows affinity-mask failure diagnostics.

• JNA handling changed materially over this period: the project moved to newer JNA releases and later added a minimum JNA major-version check. Users with constrained or old operating-system images should verify the bundled or installed JNA version when upgrading.

• CPU selection became more explicit and easier to diagnose. The release history includes explicit CPU-list acquisition, descriptive core names for MicroJitterSampler, support for very small CPU-count systems, lower-noise warnings, and clearer invalid CPU id logging.

2. Unreleased updates since Java-Thread-Affinity-2026.2

These entries are based on remote branches visible on 2026-04-28. They are not published release artefacts and may change before the next tag.

Date	Ref	Main change	Benefit / impact
2026-04-18	[N] Non-functional origin/sausage/docs-*	Documentation-only branch set covering branch-reference updates, broken URL replacement, HTTPS link upgrades, typo fixes, UK English spelling, and copyright-year clean-up.	Improves documentation accuracy and project consistency. No runtime or API impact.
2026-03-30	[N] Non-functional origin/feature/junit5	Migrates tests to JUnit 5, makes Pax Exam migration status explicit, and adjusts temporary-directory cleanup for Windows JNA DLL locking during tests.	Modernises the test suite and improves cross-platform test reliability. No library runtime behaviour change was identified.
2026-01-28	[N] Non-functional origin/develop, origin/ea	Post-release Maven state reset after Java-Thread-Affinity-2026.2.	Keeps the development line ready for the next snapshot cycle. No user-facing behaviour change.

3. Release summary

Date	Release	Main change	Benefit / impact
2026-01-28	[N] Non-functional Java-Thread-Affinity-2026.2	Aligned Maven versions to Chronicle BOM 2026.2; POM-only change from 2026.1.	Use when aligning with the Chronicle 2026.2 dependency stack. No user-facing behaviour change is expected from 2026.1.
2026-01-28	[N] Non-functional Java-Thread-Affinity-2026.1	Aligned Maven versions to Chronicle BOM 2026.1 after the 2026.0 release.	Provides release-train consistency for users consuming the Chronicle 2026.1 stack. The diff from 2026.0 is POM-only.
2026-01-28	[F] Functional Java-Thread-Affinity-2026.0	Moved to calendar versioning and java-parent-pom 2026.0; carried forward the 3.27ea1 functional changes and added quality-profile, JaCoCo, dependency smoke-test, licence/header, and documentation clean-up.	Establishes the 2026 baseline for users moving from the latest stable 3.26 line. Users get the modern Java, CPU validation, and hyper-threaded core fixes plus cleaner build governance.
2025-07-23	[N] Non-functional Java-Thread-Affinity-3.26.9	Stable 3.26 maintenance release with parent/BOM version updates only.	Low-risk update for users staying on the 3.26 stable line and wanting dependency alignment without behaviour changes.
2025-07-09	[F] Functional Java-Thread-Affinity-3.27ea1	Fixed Java 9+ support paths, improved AffinityLock CPU id validation and logging, updated acquireCore() to lock and release all logical CPUs for a hyper-threaded core, deprecated the one-id LockChecker.obtainLock path, expanded tests, and refreshed README/requirements documentation.	Improves correctness on modern JDKs and hyper-threaded hosts. Invalid CPU ids fail earlier, diagnostics are clearer, and custom LockChecker implementations may need a small source update.
2024-11-15	[N] Non-functional Java-Thread-Affinity-3.27ea0	Started the 3.27 early-access train and aligned parent/third-party BOM versions.	Useful for consumers testing the next release train. No major functional change over the contemporary 3.26 stable release was identified.
2024-11-15	[N] Non-functional Java-Thread-Affinity-3.26.8	Promoted the 3.26 line to a stable release after the early-access train and aligned to release POM versions.	Stable entry point for the 3.26 changes: modern-JDK compatibility, dependency validation, native-build scoping, and the deprecated API removal first introduced in the EA line.
2024-10-14	[F] Functional Java-Thread-Affinity-3.26ea6	Fixed a null-pointer issue and moved to a later 2.26ea BOM.	Improves reliability for users testing the 3.26 early-access line.
2024-07-19	[F] Functional Java-Thread-Affinity-3.26ea5	Added rdtsc support for ARM 64-bit and 32-bit, and made retry-after-lock-file-failure logging informational.	Improves timing support on ARM hosts and reduces unnecessary warning noise during recoverable lock acquisition retries.
2024-06-15	[F] Functional Java-Thread-Affinity-3.26ea4	First successful 3.26 early-access release after release-train version alignment; included parent POM updates, compiler warning clean-up, Java 21 test adjustments, JNA minimum-version checking, Linux-only native build activation, and removal of the long-deprecated AffinitySupport compatibility class.	Opened the 3.26 line for validation on newer build tooling and JDKs. Applications still using AffinitySupport need to migrate to Affinity.
2023-01-11	[N] Non-functional Java-Thread-Affinity-3.23.3	Updated to later 2.23 dependency versions and fixed build references to unavailable stable artefacts.	Restores a cleaner build/dependency resolution path for 3.23 users.
2022-09-29	[N] Non-functional Java-Thread-Affinity-3.23.2	Stabilised the 3.23 line by de-snapshotting the third-party BOM and switching to stable 2.23 versions.	Provides a stable dependency baseline for users not taking early-access builds.
2022-09-07	[F] Functional Java-Thread-Affinity-3.23ea1	Delayed a warning until an affinity lock is actually used and updated Maven execution tooling.	Reduces startup noise for applications that include the library but do not immediately bind threads.
2022-08-08	[F] Functional Java-Thread-Affinity-3.23ea0	Handled ClosedByInterruptException when acquireLock() is interrupted, and changed too-high CPU id handling from an exception to a warning.	Makes interrupted lock acquisition cleaner and avoids abrupt failure when a CPU id cannot be honoured on the current host.
2022-01-31	[F] Functional Java-Thread-Affinity-3.21ea83	Added descriptive core-name support for MicroJitterSampler, supported oligocore agents, and aligned to a newer 2.22ea BOM.	Improves targeted jitter sampling and operation on systems with very small CPU counts.
2021-11-03	[F] Functional Java-Thread-Affinity-3.21ea82	Handled OverlappingFileLockException, restored executable permissions on the native Makefile, and moved test process launching to chronicle-test-framework.	Improves multi-process lock robustness and keeps build/test infrastructure aligned with Chronicle tooling.
2021-10-28	[F] Functional Java-Thread-Affinity-3.21ea81	Reworked file-lock metadata handling and multi-process affinity tests around a reproduced lock-handling issue.	Improves correctness when processes contend for lock metadata and makes failures easier to diagnose.
2021-10-18	[F] Functional Java-Thread-Affinity-3.21ea80	Fixed getMetaInfo when another process holds the lock, improved multi-process test logging, and disabled unsuitable tests on non-Linux builds.	Improves lock metadata reliability under contention and reduces cross-platform test noise.
2021-06-22	[F] Functional Java-Thread-Affinity-3.21ea5	Updated to JNA 5.8.0, cleaned up deprecation state, and made the native Makefile optional for easier Windows builds.	Improves native-library compatibility and reduces friction when building on Windows.
2021-06-17	[F] Functional Java-Thread-Affinity-3.21ea4	Allowed for disabled CPUs, warned when Windows SetThreadAffinityMask silently failed, retained the previous affinity mask on that failure, and fixed AffinityThreadFactory so every created thread is bound.	Improves correctness on hosts with offline CPUs, makes Windows failures visible, and fixes a thread-factory binding bug.
2021-06-16	[N] Non-functional Java-Thread-Affinity-3.21ea3	Release-train/BOM update after 3.21ea2.	Dependency alignment release; no substantial user-facing source change was identified.
2021-05-27	[N] Non-functional Java-Thread-Affinity-3.21ea2	Republished the Java 12+ compatibility work under the Java-Thread-Affinity-* tag naming and moved to a later 2.21ea BOM.	Use this rather than affinity-3.21ea1.1 when following the newer project tag naming.
2021-05-26	[F] Functional affinity-3.21ea1.1	Removed custom java.lang classes and NonForkingAffinityLock, improved lock-file deletion logging, and moved README imagery under docs/images.	Makes the library behave better with Java versions that enforce module boundaries, especially Java 12 and later.
2021-02-22	[N] Non-functional Java-Thread-Affinity-3.21ea1	Updated early-access BOM versions, normalised line endings, and restored native Makefile execute permissions in Git.	Build and packaging clean-up for the 3.21ea line; no user-facing runtime behaviour change was identified.
2021-01-13	[F] Functional Java-Thread-Affinity-3.21ea0	Started the 3.21 early-access line; added ppc64le support, allowed -Daffinity.reserved masks beyond 64 cores, and added an AffinityLock.acquireLock path that can choose from an explicit CPU list.	Improves operation on large-core-count and ppc64le systems, and gives callers tighter control over CPU selection.
2020-09-16	[F] Functional affinity-3.20.0	Started the 3.20 release-train naming while carrying the lock-release change that allows AffinityLock release without resetting the current thread.	Useful for consumers following the 3.20 train; preserves the same lock-release benefit published as 3.2.4.
2020-09-16	[F] Functional affinity-3.2.4	Allowed AffinityLock to be released without resetting the current thread, avoided releasing affinity when it had not been narrowed, and fixed FileLockBasedLockChecker so it does not release locks held by other processes.	Reduces accidental affinity changes and improves multi-process lock safety.
2020-04-17	[F] Functional Java-Thread-Affinity-3.2.3	Handled no-affinity environments more gracefully and continued when /proc/cpuinfo is unusual, such as in some LXC or virtualised environments.	Improves startup resilience on containers and virtual machines where CPU topology data is incomplete or non-standard.

4. Notes for maintainers

The release history contains several release-train commits whose only effective change is Maven version alignment. Those releases are still listed because they are published artefacts, but their impact is intentionally described as dependency or build alignment rather than runtime behaviour.

When preparing future release notes, prefer summarising user impact rather than copying raw commit subjects. The most useful recurring categories are API compatibility, supported Java versions, supported operating systems, lock-file behaviour, dependency/BOM alignment, and diagnostics.