Senior Java Engineer | OpenKM, JavaFX & Software Modernization

I am Saul Hidalgo, a Computer Engineer, Senior Java Developer, and Founder of Saul Technologies, with more than 15 years of experience developing, maintaining, integrating, converting, and modernizing software.

My main specialization is Java, with extensive experience in Java 8, 11, 17, and 21, Spring Boot, Hibernate/JPA, Maven, Tomcat, JavaFX, Swing, Eclipse RCP, REST APIs, PostgreSQL, MariaDB, MySQL, SQLite, Docker, Linux, Git, GitHub, and OpenKM.

I have contributed to software used in UK national security and defense, document management, financial modeling, industrial companies, retail businesses, scientific applications, and academic environments including Harvard Business Publishing.

One of my longest-running projects was Debrief, a maritime-analysis platform used in UK defense environments. I worked as a core developer for about six years, making more than 1,250 contributions. My work included new features, maintenance, performance optimization, database integrations, UI development, media export, scripting integrations, and work related to Debrief NG and Debrief Lite.

I also have extensive OpenKM Document Management System experience, including workflows, automations, scheduled tasks, reports, metadata, REST and Java API integrations, authentication, retention, backups, upgrades, and custom extensions.

A major part of my work is legacy modernization and code conversion. Projects include converting a complex financial Excel model into pure Java for Forio and Harvard Business Publishing, translating more than 11,000 lines of Matlab into C# for scientific simulations, converting hundreds of Excel VBA macros into Go, and migrating Java applications to newer versions.

I have ported algorithms and business logic between Java, Go, Python, C, C++, C#, Delphi, VBA, and Matlab. I do not treat conversion as simple line-by-line translation. I first understand the algorithms, data flow, dependencies, expected results, and edge cases, then reproduce the required behavior reliably in the target technology.

My POS and retail experience includes a system deployed across 44 branches with inventory, invoicing, credit notes, fiscal and thermal printers, Zebra label printers, barcode readers, customer displays, permissions, and reports.

I have a strong background in algorithms, data structures, dynamic programming, graph algorithms, string processing, and performance optimization. I previously taught Algorithms Laboratories at Universidad Simón Bolívar using Java and Python.

I focus on understanding the real business requirement, preserving critical behavior, reducing technical risk, and delivering maintainable solutions. I am available for development, maintenance, modernization, debugging, integrations, migrations, and complex existing codebases.

GitHub: saulhidalgoaular

Please feel free to contact me and tell me about your project.

Work Terms

I am available for both hourly and fixed-price projects.

For well-defined projects with clear requirements, I can provide a fixed-price quotation together with the expected scope and delivery plan.

For maintenance, debugging, modernization, integrations, or projects involving an existing codebase, I normally review the current system first before providing a detailed estimate. This helps avoid unrealistic estimates when the complexity of the existing software is not yet known.

For hourly projects, work can be tracked through Guru.com and progress can be reported regularly.

For fixed-price projects, I prefer dividing larger projects into milestones with clearly defined deliverables and payments.

Any significant changes or additions to the agreed scope will be discussed before additional work is performed.

Communication is primarily through Guru.com, email, Slack, or another agreed platform. I am comfortable working independently as well as collaborating with existing development teams.

Source code and project deliverables are provided according to the agreed milestones and project requirements.

My goal is to maintain clear communication, realistic estimates, and transparent progress throughout the project.