Tag
Traces, Tempo and the LGTM stack
Wiring Spring Boot 4 + Spring Batch 6 to emit job/step traces into Tempo and spring_batch_* metrics into Prometheus — and the four config traps that each failed the same way: green build, zero errors, nothing exported.
I'm a Spring/Kafka backend engineer who could read Python but never wrote it. The AI world pulled me in, so I learned it by building a 10-lesson course that maps every concept back to Java, then built the tutor agent that taught me.
What @TransactionalEventListener actually fires on commit, on rollback, and on neither -- plus a write inside AFTER_COMMIT that survives or vanishes depending on your connection pool. Measured in a playground, not quoted from the Javadoc.
Spring's plain @EventListener runs on your thread, inside your transaction, before your next line — and a chained event is fully handled before the original finishes. Everything here was verified by running it, not by reading the reference page.
A fire-and-forget @Async listener turns every SMTP hiccup into a lost message. Here is how @TransactionalEventListener plus an event publication table makes it durable — and the four ways that setup silently does nothing.
Building agents on the JVM with Embabel · Part 10
When an Embabel action needs two objects of the same type, binding becomes two declarations that must agree — and nothing cross-checks them. Get them out of step and you get a startup exception, an unreachable goal, or a confident wrong answer, depending on which half you forgot.
Building agents on the JVM with Embabel · Part 9
Ask the same question twice in one session and the planner drops a step. Not a cache — a consequence of A* refusing to schedule an action whose output is already on the blackboard, for better and for worse.
Building agents on the JVM with Embabel · Part 7
My agent refused to run a single action. The @Condition gate was FALSE and nothing in the agent could ever make it TRUE, because Embabel builds an action's effects from what you declare, not from what your condition reads.
Building agents on the JVM with Embabel · Part 6
Turning my JVM agents into MCP tools took one dependency and one annotation. It also took three silent failures -- a starter that suppresses the web server, a shell that eats your CLI flags, and an annotation default that publishes exactly zero tools without telling you.
Building agents on the JVM with Embabel · Part 3
An LLM cannot know a live account balance, and in banking a confidently hallucinated number is a disaster. The fix is a tool. Here's how @LlmTool works in Embabel on the JVM, plus the one API gotcha that cost me a compile.