About Me (Brief)
I am a Java developer with commercial experience in building and developing web applications.
I mainly specialize in backend development based on the Spring Framework, but I also work full-stack, using Angular (and other frontend technologies), and more recently, Python.
I have 2 years of commercial experience as a Software Developer in the financial industry and I am currently working on freelance projects involving the development, maintenance, and deployment of web applications.
On a daily basis, I work with Java, Spring Boot, Python, SQL, Docker, and frontend technologies.
Additionally, I develop my own projects where I experiment with Python, AI, and automation of data and image processing.
I hold the Oracle Certified Professional: Java SE 17 Developer certification.
I have a technical and IT education (MSc Eng.) and postgraduate studies in Java programming more.
Technologies I Work With
- Java;
- Kotlin;
- JavaScript / TypeScript;
- Python;
- HTML, CSS;
- SQL;
Frameworks, Interfaces and Standards:
- Spring Framework;
- Jakarta EE;
- REST;
- JDBC, JPA, Hibernate, CRUD;
- Angular, AngularJS, React;
- Django, FastAPI;
- MySQL, PostgreSQL, MongoDB;
- JUnit, Spock, Mockito, Liquibase;
- Docker, Git, GitHub, GitLab, Dokploy, Jenkins;
- Grafana, Prometheus, ELK;
Skills
- Knowledge of Java and Kotlin at an intermediate level and experience in developing applications in these languages;
- Ability to work with HTML, CSS, JavaScript, as well as Angular and AngularJS frameworks, and commercial experience in developing services using Angular;
- Knowledge of Python and experience in creating, developing, and maintaining applications in this language, mainly within freelance projects;
- Knowledge and experience in working with relational databases and SQL, as well as NoSQL databases such as MongoDB;
- Familiarity with version control tools and CI/CD (Git, Jenkins, Docker, Dokploy);
- Experience and ability to work in a development team using version control systems;
- Practical experience working in Agile methodologies (Jira, Confluence).
Practical Skills
- REST API design
- Spring Boot / Spring Security
- Relational and non-relational databases
- Unit and integration testing
- Docker and VPS deployment
- External API integrations
- CI/CD
- Authentication & Authorization
- Full-stack development
My Projects
Quiz-Master
A continuously developed educational platform enabling the creation and solving of thematic quizzes. The project is designed as a scalable full-stack solution with backend answer validation, result tracking, and extensibility for future features.
Technologies
- Backend written in Java using the Spring framework;
- Frontend built with Angular, using Bootstrap;
- Uses MongoDB NoSQL database and Liquibase for migrations;
- Testing uses (in addition to Java) Groovy, Spock, and RestAssured;
Features
- taking quizzes without login;
- time and score tracking;
- backend answer validation;
- dynamic shuffling of questions and answers;
- quiz and question management;
- result summary generation;
Planned Development
- user accounts;
- statistics and history of results;
- comments on questions;
- extended admin panel;
Links
AI Image Processing Platform
A batch image processing platform powered by AI, designed to automate product, catalog, and marketplace image editing.
The application enables simultaneous processing of multiple images using operations such as resize, format conversion, background removal, AI upscaling, and quality enhancement.
Technologies
- Python
- FastAPI
- Pillow
- OpenCV
Features
- single file and ZIP uploads;
- batch image processing;
- aspect-ratio-preserving resizing;
- JPEG / PNG / WEBP / AVIF conversion;
- local background removal;
- advanced AI background removal;
- AI upscaling;
- quality enhancement;
Links
J-Countant
An application supporting financial management for small businesses. The system enables document tracking, transaction analysis, and automatic calculation of taxes and financial balances.
The project is based on a REST architecture with separate frontend and backend components.
Technologies
- Backend written in Java using the Spring framework;
- Uses PostgreSQL relational database;
- Spring components: Spring Security, Spring Web, Spring Data;
- Additional technologies: JPA, Hibernate, Liquibase, Hibernate Validator;
- Testing tools: JUnit, Mockito, AssertJ, Testcontainers;
- Deployment technologies: Git, Docker, Docker Compose, AWS;
- Frontend built with AngularJS
Features
- user authentication and registration;
- invoice and transaction management;
- tax and balance calculations;
- financial analysis over selected date ranges;
- financial report generation;
Links
My-Books
A web application that allows users to build their own book library by integrating with the Google Books API.
The project focuses on personal collection management, user authentication, and external API integration.
Technologies
- Backend written in Java using the Spring framework;
- Uses PostgreSQL relational database;
- Frontend built with React
- Additional technologies: Liquibase, Docker, Gradle, JWT;
Features
- user registration and login;
- book search via Google Books API;
- adding books to personal library;
- marking books as read;
- pagination of results;
Links
Utility Recorder
A desktop tool for monitoring utility consumption (e.g. electricity, water) with persistent storage, analysis, and visualization capabilities.
Technologies
- Application written in Java;
- Uses standard GUI libraries such as Swing;
Features
- record creation and editing;
- consumption analysis;
- average calculations;
- chart generation;
Links
Logic Game: Number Puzzle
A simple logic game where blocks are moved to arrange them in the correct order.
Technologies
- Java;
- Basic Java AWT libraries for desktop applications;
Features
- blocks are shuffled automatically at game start;
- ability to change difficulty (number of blocks) and reset the game;
- move counter and game timer;
Links
More About Me
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Born in 1984, living in Zielona Góra.
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2003–2008: studies in Technical and IT Education at the University of Zielona Góra.
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Many years of experience in production work, including process supervision, machine setup, and maintenance.
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Experience as a CNC Machine Operator (including a course in CNC operation and programming).
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2020–2022: focus on programming and non-commercial projects.
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2020/2021 Postgraduate Studies: Java Application Programming, WSB University in Wrocław.
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Feb 2023 – Jan 2025 job as a Junior Software Developer in a financial company. Role focused on Java, also involving Kotlin and frontend work with Angular and related technologies.
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June 2025: started freelance business (sole proprietorship) delivering development, maintenance, and extension of projects mainly in Java and Python. Scope includes backend, frontend, and deployment.
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December 2025: passed Oracle Certified Professional: Java SE 17 Developer certification.
Contact
- gerstel.tomasz@gmail.com
- linkedin.com/in/tgerstel
- github.com