Java Software Engineer

Job description

Build and improve real-world Java desktop software in a small, influential engineering team where your technical decisions, ideas, and leadership will genuinely matter.
Apply now, read the job details by scrolling down Double check you have the necessary skills before sending an application.
Hands-on Java desktop software role focused on Swing-based commercial applications - not web development.
About Us
Semantics 21 is a multi-award-winning UK software company developing specialist desktop software used internationally within public safety and investigative environments.
Our technology helps organisations process and review digital evidence more effectively, supporting work that can have genuine real-world impact in areas including child protection and public safety.
We are growing our engineering team and are looking for a Senior Java Software Engineer to help develop large-scale desktop applications used operationally by organisations internationally.
Despite the sensitive environments our software supports, development staff are never exposed to illegal or disturbing material as part of their role.
The Role
This is a hands-on software engineering role focused on long-term desktop application development - not web development.
You will work across both existing and new applications, contributing to software used daily in real operational environments where reliability, usability, and performance genuinely matter.
This role may suit an experienced developer already operating at senior level, or a strong Java developer ready to step into greater technical ownership, mentoring, and long-term product influence.
This role is ideal for someone who enjoys building real software products, solving practical engineering problems, and contributing ideas within a smaller technical team where your voice and technical direction genuinely matter.
We are looking for a Java Software Engineer, or a strong Java developer to help develop and improve large-scale desktop applications used operationally by organisations internationally.
You will be involved in:
Desktop application development using Java and Swing, with some JavaFX where appropriate
Improving and maintaining large commercial codebases
Performance optimisation and troubleshooting
Designing intuitive desktop user interfaces
Database integration using technologies such as MySQL and SQLite
File processing, reporting, and data handling
Contributing ideas, innovation, and long-term technical improvements across the wider platform
Helping guide development standards, architecture decisions, and future technical direction
We use modern development tooling and actively support sensible use of AI-assisted development tools, such as Codex, where they improve productivity, code understanding, testing, or development workflow.
Why Join Us / What We Offer
We are a smaller engineering team where developers are encouraged to contribute ideas, improvements, and innovation - not simply complete assigned tasks.
Developers work directly with the CEO within a flat management structure.

This gives the development team direct access to someone with hands-on software development, architecture, customer, and investigator experience.
Your input will directly influence products, workflows, technical direction, and long-term development decisions across the company.
This is not an environment where developers are treated as interchangeable resources or isolated from decision-making.

Your ideas will be heard, challenged, and where appropriate, implemented.
This role suits developers who enjoy building real, long-term software products rather than short-lived web, marketing, or internal dashboard projects.
What Were Looking For
We are ideally looking for someone with:
Strong commercial Java development experience
Experience developing desktop applications using Swing and/or JavaFX
Strong understanding of Core Java and object-oriented programming
Experience working within larger or long-term codebases
Good debugging, analytical, and problem-solving skills
Ability to work independently and take ownership of technical challenges
Ability to think beyond individual tickets and contribute to longer-term product improvement
Strong written and verbal English communication skills
Experience with any of the following would also be beneficial:
Multithreading/concurrency
MySQL or SQLite
JasperReports
Git
File parsing and processing
AI-assisted development workflows
Strong personal projects, GitHub work, or demonstrable practical coding ability are valued more highly than formal qualifications alone.
Please include links to previous work, GitHub, portfolio projects, screenshots, or other examples in your CV or application where available.
Working Environment
Based from our Stafford (ST18) office
This is an office-based role at our Stafford office.
Shortlisted candidates maybe welcomed into the office as part of the process
Full-time, permanent role
Free onsite parking
We support flexible working hours where possible.

Most roles are based around a 7.5-hour working day, Monday-Friday, during normal office hours, with start and finish times agreed around team and business needs.

Typical patterns may include 08:00-16:00, 09:00-17:00, or 10:00-18:00.
What We Offer
£30,000 - £35,000 depending on experience depending on experience, capability, and level of responsibility
Long-term stable product development work
Real influence within a growing engineering team
Direct involvement in product and technical direction
Modern development environment and tooling
Sensible use of AI-assisted development tools
Opportunities for progression and increased technical responsibility over time
Friendly, supportive, and low-bureaucracy working environment
Important Note
This role is specifically focused on Java desktop software engineering.
Applicants focused primarily on web development frameworks are unlikely to be suitable for this position.
Please include an up-to-date CV.

A formal cover letter is not required, but a short note explaining your relevant Java desktop experience, project examples, or links to previous work is welcome.
We review applications as they arrive and aim to contact suitable candidates promptly rather than waiting until the closing date.

The role may close once we find the right candidate, so early applications are encouraged.
To help us assess applications fairly, please answer the application questions and include relevant links or examples where available.

Applications with incomplete information may be harder for us to assess and may not be progressed.
You can learn more about our products, videos, and webinars on our website.

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Direct applicants only - no recruitment agencies.

Required Skill Profession

Information Technology