LAJVM — ArticlesAll the articles. Filter by topic, by tag, or search for a word.https://lajvm.fr/en-USMaking architecture hold up over timehttps://lajvm.fr/en/testing-architecture-archunit-konsist/https://lajvm.fr/en/testing-architecture-archunit-konsist/An architecture rule nobody checks does not survive six months of sprints. It only holds if it breaks the build, like any other test.Sat, 01 Aug 2026 00:00:00 GMTArchitecture and designReading GC logs without external toolshttps://lajvm.fr/en/reading-gc-logs/https://lajvm.fr/en/reading-gc-logs/A gc.log file can be read by hand. Once you can decode the summary line and the region-by-region breakdown, you can spot a problem before opening any profiler.Thu, 23 Jul 2026 00:00:00 GMTMemory and garbage collectorVirtual threads in production: what actually breakshttps://lajvm.fr/en/virtual-threads-in-production/https://lajvm.fr/en/virtual-threads-in-production/Since JDK 24, synchronized no longer pins the carrier thread. Most articles online still tell you to avoid it. What actually breaks in production is somewhere else.Thu, 16 Jul 2026 00:00:00 GMTRuntime and productionTuning the JVM in a containerhttps://lajvm.fr/en/tuning-the-jvm-in-a-container/https://lajvm.fr/en/tuning-the-jvm-in-a-container/An app that runs fine locally but gets killed on Kubernetes is almost always a story of misread cgroup limits and a badly sized heap. What to tune, and why.Thu, 09 Jul 2026 00:00:00 GMTRuntime and productionDiagnosing a memory leak with a heap dumphttps://lajvm.fr/en/diagnosing-a-memory-leak-with-a-heap-dump/https://lajvm.fr/en/diagnosing-a-memory-leak-with-a-heap-dump/When memory climbs and never comes back down, the heap dump holds every object in the heap. The job is to find which one keeps all the memory, and why the GC can't free it.Wed, 24 Jun 2026 00:00:00 GMTMemory and garbage collectorReading a thread dump with jstackhttps://lajvm.fr/en/reading-a-thread-dump-with-jstack/https://lajvm.fr/en/reading-a-thread-dump-with-jstack/The JDK tool that photographs the state of every thread in a live JVM. Enough to see in seconds who is stuck, on what, and why.Sun, 21 Jun 2026 00:00:00 GMTProfiling and performanceTuning the JVM garbage collectorhttps://lajvm.fr/en/tuning-the-jvm-garbage-collector/https://lajvm.fr/en/tuning-the-jvm-garbage-collector/GC tuning starts with deciding what you optimise and reading the logs, not with copying flags from a forum. A tour of the levers that actually matter.Thu, 18 Jun 2026 00:00:00 GMTMemory and garbage collectorObservability with Micronaut: metrics, traces, and the context-propagation traphttps://lajvm.fr/en/observability-in-micronaut/https://lajvm.fr/en/observability-in-micronaut/Wiring Micrometer, OpenTelemetry and structured logs into Micronaut, plus the one thing that quietly breaks everything: losing the propagated context when you hand work to another thread.Tue, 16 Jun 2026 00:00:00 GMTRuntime and productionHexagonal architecture and how to implement it in Spring Boothttps://lajvm.fr/en/hexagonal-architecture-in-spring-boot/https://lajvm.fr/en/hexagonal-architecture-in-spring-boot/Ports & adapters, concretely: a domain with no Spring annotations, ports as interfaces, and Spring demoted to an adapter. With the package layout.Sat, 13 Jun 2026 00:00:00 GMTArchitecture and designHow to read a flamegraphhttps://lajvm.fr/en/how-to-read-a-flamegraph/https://lajvm.fr/en/how-to-read-a-flamegraph/Width = time, height = stack depth, and above all: the horizontal axis is not time. The reading grid in a few minutes.Sat, 13 Jun 2026 00:00:00 GMTProfiling and performanceProfiling the JVM with async-profilerhttps://lajvm.fr/en/profiling-the-jvm-with-async-profiler/https://lajvm.fr/en/profiling-the-jvm-with-async-profiler/A sampling profiler that doesn't lie about safepoints, runs in production with minimal overhead, and outputs a flamegraph directly.Sat, 13 Jun 2026 00:00:00 GMTProfiling and performance