September, 2026

• 15 September

  Can You Explain the Diff Your AI Agent Just Wrote?

  Author: Viktoria Evdokimova Original post on Foojay: Read More Every Java developer has been in a code review where the question is simple: What does this method do? The answer used to tell you something.

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• 15 September

  How I Built an AI Assistant for My Career with Java, Spring AI, and MongoDB

  Author: Ricardo Mello Original post on Foojay: Read More How one developer built a personal AI assistant in Java using Spring AI, MongoDB Vector Search, conversation memory, and tool calling with Calendly.

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• 9 September

  Masking a JVM thread dump without breaking the analysis

  Author: Felipe Maschio Original post on Foojay: Read More A few weeks ago I posted on r/java about detecting virtual thread pinning from a plain thread dump. The technical discussion was fine. The comment that stuck with me had nothing to do with pinning: “the problem isn’t taking the dump, it’s that uploading a production dump to a third-party site …

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• 8 September

  Debugging Is Invariant Discovery: What One Kafka Session Taught Us About AI Agents

  Author: Viktoria Evdokimova Original post on Foojay: Read More #foojay-site-content for WordPress credentials (already have them from the first post). 2. foojay.io/wp-admin -> new post, paste this Markdown, Save Draft, Preview in a new tab. 3. Code blocks: “Convert to blocks” / “Code Insert”, set language Java for the two Java snippets. 4. Featured image: required. Use articles/explyt-kafka-tid-invariant/en/cover-one-symptom-ten-problems.png (1672×941, branded, …

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• 8 September

  Community Spotlight: BoxLang Express Brings Node-Style HTTP to the JVM

  Author: Cristobal Escobar Original post on Foojay: Read More If you’ve spent years in Spring Boot, Micronaut, or Jakarta EE, “web framework” usually means a servlet container, an embedded Tomcat or Netty, a build step, and a fat jar before anything answers a request. What if you could skip all of that and still be on the JVM? BoxLang Express, …

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• 8 September

  “Commit created” — but it isn’t: why the agent’s word needs external verification, and what the mistake costs

  Author: Viktoria Evdokimova Original post on Foojay: Read More A detailed report reads like proof. The agent lists the files it touched, names the branch, quotes a commit hash, adds a test count and closes with “done”. The work has a shape. The shape looks right. You have six more tickets. The report is model output. The commit, if it …

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• 8 September

  From OpenTelemetry to DuckDB

  Author: Geertjan Wielenga Original post on Foojay: Read More Observability platforms generally expect you to do your analysis inside them, using their query language and their dashboards. That works for the questions you already know you have. It works less well for the ad-hoc ones: a quick percentile, a pivot by status code, or “which service is actually eating the …

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• 7 September

  Featured Foojay Authors for September 2026: Marit van Dijk and Graeme Robinson

  Author: Frank Delporte Original post on Foojay: Read More Foojay 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 each month as Featured Authors. After Igor and Steve in July, and Cristobal and Shai in August, September belongs to Marit van …

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• 7 September

  Bringing Raspberry Pico to Quarkus with Firmata

  Author: Igor De Souza Original post on Foojay: Read More Java applications are usually associated with APIs, databases, messaging systems, and cloud infrastructure. But Java can also interact with the physical world—reading sensors, controlling LEDs, driving motors, and communicating with microcontrollers. That is the goal of Quarkus Firmata, a new Quarkus extension that connects Quarkus applications to Firmata-compatible boards such …

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• 4 September

  From Spec-Driven Development to Living Specifications in Java Projects

  Author: Maximillian Arruda Original post on Foojay: Read More From Spec-Driven Development to Living Specifications in Java Projects Coding agents have changed the speed at which we can produce software. But producing code faster does not automatically mean producing better software. As I started using agents more frequently in real-world software development, one question became increasingly important: how do we …

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