GeezerVison

`$ whoami`

Backend engineer with deep expertise in Java, Go, and Rust, focused on distributed systems and large-scale modernization. At Itaú Unibanco — one of Latin America's largest banks — I lead the transformation of legacy monoliths into resilient, scalable microservices.

Beyond my day job, I'm a committer on Apache TomEE and contributor to Jakarta EE, MicroProfile, and EclipseEE4J — actively shaping the future of enterprise Java.

Currently on a journey learning Rust 🦀 — exploring memory safety, testing, and systems programming.

`$ whoami --code`

☕ Java

public class DanielDias implements SoftwareEngineer {

    private final String employer  = "Itaú Unibanco";
    private final String oss       = "Apache TomEE Committer | Jakarta EE & EclipseEE4J Contributor";
    private final String focus     = "Distributed Systems · Clean Architecture · Open Source";
    private final String learning  = "Rust 🦀";
    private final String[] stack   = {"Java", "Go", "Rust"};

    @Override
    public String passion() {
        return "Building software that evolves with the business — clean, simple, maintainable.";
    }
}

🐹 Go

package main

import "fmt"

type SoftwareEngineer interface {
    passion() string
}

type DanielDias struct {
    employer string
    oss      string
    focus    string
    learning string
    stack    []string
}

func (d DanielDias) passion() string {
    return "Building software that evolves with the business — clean, simple, maintainable."
}

func main() {
    daniel := DanielDias{
        employer: "Itaú Unibanco",
        oss:      "Apache TomEE Committer | Jakarta EE & EclipseEE4J Contributor",
        focus:    "Distributed Systems · Clean Architecture · Open Source",
        learning: "Rust 🦀",
        stack:    []string{"Java", "Go", "Rust"},
    }
    fmt.Println(daniel.passion())
}

🦀 Rust

trait SoftwareEngineer {
    fn passion(&self) -> &'static str;
}

struct DanielDias {
    employer: &'static str,
    oss:      &'static str,
    focus:    &'static str,
    learning: &'static str,
    stack:    [&'static str; 3],
}

impl SoftwareEngineer for DanielDias {
    fn passion(&self) -> &'static str {
        "Building software that evolves with the business — clean, simple, maintainable."
    }
}

fn main() {
    let daniel = DanielDias {
        employer: "Itaú Unibanco",
        oss:      "Apache TomEE Committer | Jakarta EE & EclipseEE4J Contributor",
        focus:    "Distributed Systems · Clean Architecture · Open Source",
        learning: "Rust 🦀",
        stack:    ["Java", "Go", "Rust"],
    };
    println!("{}", daniel.passion());
}

`$ cat /stack`

Layer	Technologies
Languages
Frameworks
Messaging
Data
Infra
Testing
Principles	`DDD` `Clean Architecture` `SOLID` `Hexagonal` `Event-Driven`

`$ cat /opensource`

Open source is where I give back to the community that shaped my career.

Project	Role	Description
Apache TomEE	✅ Committer	Enterprise Java runtime — core features, bug fixes & DX
Apache TomEE Site	✅ Committer	Official TomEE documentation & website
Jakarta MVC	🤝 Contributor	Jakarta MVC specification
Eclipse Krazo	🤝 Contributor	Reference implementation of Jakarta MVC
Apache DeltaSpike	🤝 Contributor	CDI extensions for Jakarta EE

`$ cat /experience`

🏦 Itaú Unibanco — Modernizing large-scale financial systems: decomposing monoliths into microservices with DDD, Clean Architecture, Kafka and Apache Camel
⚙️ API Design — Designing RESTful APIs for high-throughput, low-latency financial services
📊 Observability — Full observability with Datadog: metrics, distributed traces, dashboards and alerts
☁️ AWS Infrastructure — EC2, ECS, S3, RDS; infrastructure-as-code with Terraform
🔁 CI/CD — Building and maintaining delivery pipelines with Jenkins
📨 Distributed Messaging — Event-driven architectures with Kafka, Camel and Apache Pulsar (Java producers + Go consumers)
🛡️ Performance Tuning — Profiling and optimizing Java services under high load in production

`$ tail /blog/latest`

Writing about Java, Go, Rust, and distributed systems

2026

	Post	Tags
🦀	Testing in Rust — From Java and Go to Crates and Modules	`Rust`
🦀	My Journey Learning Rust	`Rust`
📊	A Beginner's Journey into HTTP, Load Testing, and Observability	`Observability`
🌐	Becoming an Open Source Contributor with Apache TomEE	`OSS` `Java`

2025

	Post	Tags
☕	Java Talks, Go Listens: My First Apache Pulsar App	`Java` `Go` `Pulsar`
📦	Using Jakarta Data with Apache TomEE: A Step-by-Step Tutorial	`Java` `OSS`