Friends of OpenJDK Today

Table of Contents From Orlando to AtlantaThree ways to experience JCON USASession highlightsA complete technical conference around JCONA home for the Java communityEvent informationJCON USA returns inside IBM TechXchange 2026 with two rooms of deep Java content, a dedicated community …

Table of Contents Where the reflection cost comes fromAvro, the part we built by handThe heartbreakWhat changed, measuredWhen I would not botherTakeawayI run a model layer that accepts the same business data in JSON, XML, YAML, and TOML and converts …

Table of Contents What a gateway is, mechanicallyProbing it from JavaThe boundary a Java developer should care aboutLesson one: code does not tokenize like proseLesson two: refresh the token before it dies, one per serverA checklist before you paste a …

Table of Contents What a thread dump actually leaksWhy “mask everything” doesn’t workHow a name becomes a tokenThe flow, from the point of view of someone who has never run itDoes the analysis survive?What a security team can actually checkWhere …

Table of Contents The shape of the sessionWhat the agent got rightWhat it got wrong, and why it matters for Java teamsThe agent’s only sensor was the developerThe Java lesson: write the invariant down where a test can see itWhat …

Table of Contents The itch that started itWhat’s insideMiddleware, the way you already know itTwo view engines, your choiceBuilt with a defensive postureExpress Test AppWhy this matters If you’ve spent years in Spring Boot, Micronaut, or Jakarta EE, “web framework” …

Table of Contents What the issue trackers show”Committed” and “pushed”Where the JetBrains IDE keeps the evidenceA five-minute walkthroughAcceptance checklist for agent-reported side effectsFAQConclusionSourcesA detailed report reads like proof. The agent lists the files it touched, names the branch, quotes a …

Table of Contents Why DuckDBSetup1. Install DuckDB2. Install the Dash0 CLI3. AuthenticateGetting spans out of Dash0Kicking the DuckDB tiresMaking it persistentFive useful queries1. Golden signals per service2. A latency histogram3. Pivot by status4. Share of total latency per service5. Convert …

Table of Contents Marit van DijkGraeme RobinsonThanks, and see you in OctoberFoojay wouldn’t exist without the many contributions from its community, whether it’s a single post or an ongoing stream of knowledge sharing. That’s why we highlight two of them …

Table of Contents What is Firmata?Why create a Quarkus extension?Java 25 and QuarkusBuilding the extensionConfiguring the serial connectionControlling the Raspberry Pi PicoAccessing firmata4j directlyA note about serial communication on Java 25Preparing the Pico firmwareWhat comes next? Java applications are usually …

Table of Contents The Promise of Spec-Driven DevelopmentWhat We Learned by Putting It into PracticeWhen the Specification Is Not the Source of TruthSBCE: Bringing the Specification Closer to the CodeSDD4J: Adapting to Multiple Architectures in Java ProjectsThere Is No Silver …

Table of Contents Accessing operational dataRetrieving depositor policiesActCompleteIf you haven’t read the first two parts yet, I recommend starting with Part 1: Where AI Agents Add Value and Part 2: Designing and Planning the Agent. There, we introduced the WMS …

Table of Contents Define the AgentTrigger the AgentPlanIf you arrived here without reading the first part, I recommend starting with Agentic WMS — Part 1: Where AI Agents Add Value. There, we introduced the WMS scenario, explored the replenishment problem, …

Table of Contents Modeling the WMS flowDeciding when to replenishI spent a large part of my career working in banking and logistics. In logistics, I spent more than eight years working across different stages of logistics systems, from development to …

Table of Contents The method under testA checklist you can apply with any agentJava developers reach for the debugger without thinking about it. Set a breakpoint, run the failing test, look at the variables, then decide what to change. Most …

Table of Contents The endpoints are not where the annotations areSpring runs code nothing callsThe names lie in specific, learnable waysMessaging boundaries are where the joins are wrongThe rule I ended up withWhat this has to do with reading a …