Octavio Calleya García

Software Engineer, Java & Kotlin Backend Developer

Software Craftmanship.

Delivering robust and scalable backend systems with integrity and expertise.

Resume

Contact

Projects

Showcasing impactful projects and technical achievements.

Musicott

Cross-platform desktop music player built with JavaFX and Spring Boot on top of music-commons and lirp, with local-first library management, waveform visualization and iTunes import.

Desktop

Backend

music-commons

Modular, reactive Kotlin library for managing audio libraries, playlists and waveforms, published to Maven Central and built on top of lirp.

Library

Backend

lirp

Lightweight Reactive Persistence — a Kotlin/Java library where domain entities own their reactivity and repositories persist transparently to SQL, JSON or Kafka.

Library

Backend

Experience

Professional journey and career timeline.

Software Engineer, Java Backend Engineer

Auto Fleet Control•Prague (remote)

2025 - 2026

Design, implementation and testing of a greenfield, modular Self-Contained System using Domain Driven Design, Hibernate, Spring Boot 4 and Kafka.

JavaSpring Boot+4 more

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Software Engineer, Java Backend Engineer

Cisco Systems•Prague (remote)

2024 - 2025

Design, implementation, testing, and maintenance of new features, bugfixes and architectural changes of a JVM backend (Java 8, Java 17 and Scala) using Spring Boot and React + Redux frontend.

JavaScala+3 more

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Software Engineer, Java Backend Engineer

S&P Global•Prague (remote)

2023 - 2024

Implementation, testing and maintenance of features in a Java backend system with a Swing based desktop application.

JavaJavaFX+3 more

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Contributions

Open-source contributions and community involvement.

sdk-kotlin

Building the official Kotlin SDK for CloudEvents: the core event model, attribute type system and validation, plus the build, contribution and quality foundation and supply-chain hardening. Also proposed the SDK to the CloudEvents specification.

CloudEvents

strawberry

Contributed whole-track waveform visualization on the playback seekbar, bringing to a popular open-source music player a feature born out of my own Musicott work.

Strawberry Music Player

konture

Improving a Kotlin architecture-testing library that enforces architecture rules as fast, lightweight unit tests across Kotlin Multiplatform, Android and server-side projects. Refined its rule-violation reporting so failures pinpoint the exact declaration and source location, with localized messages across all supported locales.

baole

Skills

Key skills that define my professional identity.

Java

Core language with 9+ years of professional experience across enterprise systems, microservices, and desktop applications.

Kotlin

Modern JVM language used for building reactive libraries, coroutine-based frameworks, and Spring Boot services.

Spring Framework

Deep expertise in Spring Boot, Spring MVC, and Spring ecosystem for enterprise backend development.

Concurrent Programming

Extensive experience with multithreading, reactive programming, coroutines, and high-throughput systems.

API Design

Design and implementation of RESTful APIs, OpenAPI specifications, and GraphQL schemas.

JavaFX

Desktop application development with rich UI components and media capabilities.