I take backend systems from fragile to dependable: performance, test reliability, cloud migration, and the agent tooling that speeds it all up.
8 years in tech, 5 of them building Java backends. Remote from Brasília, Brazil.
- 🔨 Building: a public repo with the Claude Code skills, hooks and statusline I use every day
- 📚 Next up: OCP Java 21 and Kafka (Confluent Fundamentals)
- ✍️ Writing: notes on running coding agents behind tests, gates and human review
Refreshed weekly by a Claude Code agent that opens a PR; I review and merge it.
| Problem | Approach | Result |
|---|---|---|
| An event-pipeline step took 10+ min and exhausted the DB connection pool | Serialized the consumer, swapped O(N) list lookups for sets, batched the inserts | 10+ min → ~6 s |
| Large-range data export crashed with OOM | End-to-end streaming: O(1) reads, paged table, SXSSF Excel, low-level PDF (SXSSF alone was not enough) | Constant memory, OOM gone |
| Inherited E2E suite with dozens of failing regressions | Removed swallowed waits and catches pattern by pattern, one small PR each, plus strict SQL seeds and cleanups | 0 failed · 0 flaky in every run |
| Legacy apps with little or no unit testing | Honest coverage (justified excludes only, dead code removed), then a coverage gate in the build | 100% on all JaCoCo counters |
| Repetitive manual steps in a Java EE → cloud migration | Google ADK agents on shared building blocks, with guardrails in 3 layers (command allowlist, timeout, output truncation) | Manual setup turned into reviewable agent runs |
Side projects: agent-code-cli-java and agent-code-cli-rust, an agent runtime written from scratch (agent loop, tools, permission gating, context compaction) in Java 25 and Rust. The Rust build sits at 96.8% coverage and ships as a 5.5 MB binary.
Agents do the legwork; gates and a human decide what ships.
flowchart LR
S[Skill<br/>versioned playbook] --> H[Hooks<br/>guardrails · statusline]
H --> A[Subagents<br/>isolated context]
A --> G{Gates<br/>tests · coverage}
G -- fail --> A
G -- pass --> R[Human review]
R --> C[Signed commit<br/>push by me]
Claude Code · Codex CLI · Antigravity CLI · MCP · Ollama. Skills repo: coming soon.
Also: WebFlux · Quarkus · JPA/Hibernate · Pub/Sub · ActiveMQ · MongoDB · Redis · Oracle · SQL Server · Keycloak · Resilience4j · Datadog · GitLab CI · JUnit · Testcontainers · JaCoCo · Playwright.
- ☕ OCP Java SE 21 (study log)
- 📨 Kafka (Confluent Fundamentals)
- 🏛️ Software architecture, DDD and event-driven design
- ✅ AWS Certified Cloud Practitioner · 🎓 BSc Computer Science (UCB) · Postgrad Full-Stack (PUCRS)
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