👋 Hey there, I'm Matheus Oliveira!

I'm a software developer focused on building high-performance, scalable, and cloud-ready applications. With a solid foundation in the Java ecosystem and Angular, I'm dedicated to creating solutions that combine robust architecture with a seamless user experience.

Currently, besides my work at Act/BMW, I'm an active contributor in the Open Source community, collaborating with major projects like Jakarta EE, JNoSQL, Quarkus, and BuildCLI. I also write about Java, cloud-native architectures, and open source on my blog, sharing knowledge and experiences with the community.

My transition from music to technology brought me sharp analytical skills and a natural ability to communicate and work in teams — essential skills for agile environments. I'm always looking for challenging projects where I can apply technology to create real impact! 🚀

📧 Get in touch: [email protected]

I believe in the power of Open Source! Here are some external projects where I've left my mark:

• pt.quarkus.io — Brazilian Portuguese localization of the official Quarkus website    🔗 My PRs
• quarkus-openapi-generator — Plugin for OpenAPI code generation    🔗 My PRs
• BuildCLI/website — Official BuildCLI documentation    🔗 My PRs
• timeless — Personal financial organization app    🔗 My PRs
• RPA_FINANC — Financial process automation    🔗 My PRs
• awesomeyou — An initiative highlighting the human side of Brazilian Open Source through a fair impact-scoring system    🔗 My PRs

Writing about Java, cloud-native architectures, and open source

• The Active Record Pattern and Hibernate Reactive: Entities That Save Themselves in Quarkus
  Entities that save themselves! Refactor your orders application to the Active Record pattern with PanacheEntity, learn when to choose Repository vs. Active Record, and enter the reactive world with Hibernate Reactive and @WithTransaction.

• AI Agent Tools in Quarkus LangChain4j: When the REST Client Becomes the LLM's Right Hand
  Build an AI agent that calls real REST APIs as tools, without writing any orchestration logic. REST Client + @Tool = automatic tool. The LLM decides when to call, which to call, and with what arguments. Everything runs locally with Ollama via Dev Services, zero API key.

• Persistence with Panache: From Spring Data JPA to the Repository Pattern in Quarkus
  No more in-memory lists! Evolve your orders application with real persistence using Hibernate ORM with Panache in the Repository pattern. Dev Services, pagination, HQL queries and the transition from Spring Data JPA.

• Quarkus Native on Knative: 5x Faster Cold Start, 20x Less Memory
  What does a 3-second cold start cost you in production? SLO breaches on every scale-from-zero event and 19x more cloud spend on memory. I benchmarked a real Quarkus app in containers and the numbers make the case.

• Java AI Libraries Compared: LangChain4j, Spring AI, and Quarkus LangChain4j
  I built the same AI app with LangChain4j, Spring AI, and Quarkus LangChain4j. One of them took 92 lines. The others took 192 and 180.

🎯 Sharing insights and experiences at tech events and meetups.

• September, 2025 - The Developers Conference: Open-Source: Standing out in your career through code (Mentorship)
• March, 2025 - SouJava JUG: BuildCLI: An Open-Source project worth knowing
• March, 2025 - BuildCLI Discord: New Member Onboarding Meeting

Here are some projects I built from scratch. Each one represents a different technical challenge and unique learnings!

💻 Backend & Cloud Native	🎨 Frontend	🗄️ Databases
☁️ Cloud & DevOps	📨 Messaging & Data	🔧 Tools & Others