Senior Java Developer (legacy project) New Bulgaria; Poland; Romania

Xebia Group; Polska; On-site; PLN 180,000 - 280,000; Full time

Job summary

Xebia Group is seeking a seasoned Java specialist to maintain and evolve a mature enterprise application, navigating a large legacy codebase and applying established architectural patterns. You will enhance stability, introduce meaningful refactors, and deliver new features in a Scrum-like environment.

The role emphasizes ownership, collaboration, and using AI-powered assistants to boost productivity while keeping quality high and engineering standards rigorous.

Qualifications

• Proven experience with large or legacy codebases.
• Ability to quickly understand complex existing systems and navigate architectures.
• Experience using AI-powered assistants to improve productivity and quality.
• Strong analytical and problem-solving skills with a pragmatic mindset.
• Willingness to own technical challenges and improve mature applications.

Responsibilities

• Developing and maintaining a mature Java application based on established architectural patterns.
• Working with a large and complex legacy codebase and gradually improving its structure and maintainability.
• Analyzing existing solutions, identifying areas for improvement, and introducing changes where they bring value.
• Developing new features while ensuring stability and reliability of existing functionality.
• Troubleshooting and resolving issues across different parts of the application.
• Contributing to code reviews, testing, and maintaining high engineering standards.
• Collaborating with other developers in a Scrum-like environment.
• Actively contributing to the technical evolution of the application and helping move the legacy forward.

Skills

Legacy codebase mastery

System understanding

AI tooling usage

Analytical problem solving

Ownership mentality

Team collaboration

English proficiency (B2+)

Tools

Claude Code

GitHub Copilot

Cursor AI

Job description

Xebia is a global AI-first, digital transformation, and engineering partner. With over 25 years of experience and a team of 5,000 professionals across 16 countries, we help organizations design and build scalable products, platforms, and data-driven solutions.

We specialize in Artificial Intelligence, Data and Cloud, Intelligent Automation, and Digital Products, combining deep technical expertise with a strong focus on engineering excellence and a people-first culture.

In the CEE region, we’re a team of nearly 1,000 experts delivering modern applications, data platforms, and AI solutions for clients such as Millennium, ING, Play, Edenred, Arabian Drilling, FedEx, Leroy Merlin, Truecaller, Volotea, Schmitz Cargobull, and many, many more. We work with leading technologies including AWS, Azure, GCP, Databricks, and Snowflake, and combine strong engineering culture with a consulting mindset and a continuous focus on growth and knowledge sharing.

You will be:

• developing and maintaining a mature Java application based on established architectural patterns,
• working with a large and complex legacy codebase and gradually improving its structure and maintainability,
• analysing existing solutions, identifying areas for improvement, and introducing changes where they bring value,
• developing new features while ensuring the stability and reliability of existing functionality,
• troubleshooting and resolving issues across different parts of the application,
• contributing to code reviews, testing, and maintaining high engineering standards,
• collaborating with other developers in a Scrum-like environment,
• actively contributing to the technical evolution of the application and helping move the legacy solution forward.

Your profile:

• proven experience working with large or legacy codebases,
• ability to quickly understand complex existing systems and navigate established architectural patterns,
• practical experience using AI-powered assistants (e.g. Claude Code, GitHub Copilot, Cursor) to improve productivity, quality, or decision-making in software delivery,
• strong analytical and problem-solving skills, with a pragmatic approach to improving existing solutions,
• confidence in introducing changes to mature applications and taking ownership of technical challenges,
• willingness to work with legacy technology and improve it rather than simply maintain the existing state,
• good communication and collaboration skills and the ability to work effectively in a team,
• good command of English (min. B2).

Work from the European Union region and a work permit are required.

Nice to have:

Experience applying GenAI in a more structured way within the SDLC, including defined workflows, prompt patterns, or tool integrations embedded into daily work.

• Interest in and familiarity with emerging AI-driven practices (e.g. agent-based workflows, automation patterns, AI-augmented development), with a willingness to explore and experiment beyond standard approaches.