Java Developer - Core Java / Desktop Software

Build real-world Java desktop software in a small, supportive engineering team where your ideas, problem-solving ability and practical coding skills will genuinely matter.

We are looking for someone with strong Core Java ability who can learn quickly, contribute early and grow with the team as we move into important upcoming projects.

This is a full-time, office-based role in Stafford. We are not recruiting for a remote position.

About Us

Semantics 21 is a multi-award-winning UK software company developing specialist software used internationally within public safety and investigative environments.

Our technology helps organisations process and review digital evidence more effectively, supporting work with genuine real-world impact in areas including child protection and public safety.

The software we build can make a real difference. This role is suited to someone who wants their work to matter and wants to help create applications that support important public safety outcomes.

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 Java development role focused on desktop software rather than web development or AI model development.

Strong practical Core Java ability is essential. Previous desktop application, Java 25, Java Swing or JavaFX experience would be highly beneficial, but we are also open to strong Java developers who can demonstrate the ability to learn quickly and adapt to desktop software development.

This role is ideal for someone with strong Java skills, good problem-solving ability, reliability, and the motivation to develop quickly within a long-term product environment.

We do use AI-assisted development tools where appropriate, and there may be opportunities to work on AI-related product features in the future. However, the immediate focus of this role is Core Java, Java Swing, desktop applications, usability, performance, reliability and maintainability.

You Will Be Involved In

• Developing Java desktop software using Core Java
• Working with larger commercial codebases
• Learning and working with Java Swing-based applications
• Debugging, testing and improving application performance
• Improving desktop user interfaces, usability and workflows
• Improving speed, reliability and maintainability
• Database integration and data handling
• Learning how long-term commercial software products are built, maintained and improved
• Contributing ideas and improvements across the development team

Why Join Us

• Work on software that supports real public safety outcomes and can make a genuine difference
• Join a smaller engineering team where your ideas, approach and technical judgement will matter
• Have a stronger voice than you may have in a large organisation
• Work directly with the CEO within a flat management structure
• Contribute to real, long-term software products used internationally
• Help improve applications that already have real users and real operational value
• Be part of a team where developers are encouraged to contribute ideas, improvements and innovation - not simply complete assigned tasks

This role suits developers who enjoy building real desktop software products rather than short-lived web, marketing or internal dashboard projects.

What We’re Looking For

We are looking for someone with:

• Good practical Core Java and object-oriented programming skills - essential
• Ability to discuss Java projects you have personally built or significantly contributed to
• Strong analytical and problem-solving ability
• Ability to write clear, practical, maintainable code
• Willingness to work on existing commercial codebases
• Interest in desktop software, user interfaces and practical product development
• Good communication skills
• Reliability, maturity and ability to work consistently from our Stafford office
• Initiative and willingness to keep learning
• Eligibility to work in the UK
• Ability to work in the UK without visa sponsorship

Background

A degree in Computer Science or equivalent practical experience would be beneficial, though we are open to candidates from different backgrounds who can demonstrate strong technical ability.

We are open to strong early-career applicants, but this is not a graduate-only training role. Candidates should be able to demonstrate practical Java ability and the confidence to contribute to real commercial software reasonably quickly.

Strong personal projects, GitHub work, portfolio examples 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 at our Stafford (ST18) office
• Full-time, office-based role
• Applicants must be able to travel reliably to our Stafford office
• Full-time, permanent position
• Free onsite parking
• Friendly and supportive working environment
• Flexible start and finish times may be agreed around team and business needs

Most roles are based around a 7.5-hour working day, Monday-Friday, during normal office hours. 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 and practical ability
• Mentoring and support from experienced developers
• Genuine opportunities for progression and increased responsibility
• Long-term product-focused development work
• Exposure to real commercial software projects from day one
• Direct access to leadership and technical decision-making
• Sensible use of AI-assisted development tools
• Opportunity to build software used in serious, meaningful operational environments

Important Note

This role is specifically focused on Core Java and desktop software development.

Applicants from Java web or backend backgrounds may be considered where they can demonstrate strong practical Core Java ability and a genuine willingness to work on desktop software.

Applicants focused primarily on web development frameworks, frontend JavaScript frameworks, AI-only work, or remote-only roles are unlikely to be suitable for this position.

Reliability and the ability to attend the Stafford office consistently are important for this role.

How to Apply

Please include an up-to-date CV.

A formal cover letter is not required, but a short note explaining your relevant Java experience, desktop software experience, project examples, GitHub links or portfolio work is welcome.

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.

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.

Direct applicants only - no recruitment agencies.

You can learn more about our products, videos and webinars at:

https://www.semantics21.com

Job reference: S21-JAVA-IN3-J2026

Pay: £30,000.00-£35,000.00 per year

Benefits:

• Company pension
• Employee mentoring programme
• Flexitime
• Free parking
• On-site parking

Ability to commute/relocate:

• Stafford ST18 0WL: reliably commute or plan to relocate before starting work (required)

Application question(s):

• Where are you currently based, and what would your daily commute to our Stafford office look like?
• Describe your Core Java experience, including any Java projects you have personally built or significantly contributed to.
• Describe any desktop application, Java Swing, JavaFX, or larger codebase experience you have. If you do not have this experience, please explain why you believe you could adapt quickly.
• If you are currently in the UK on a visa, time-limited right-to-work status, graduate visa, dependant visa, BN(O) visa, student visa, or other immigration permission, please provide brief details including visa type and expiry date. If this does not apply, please write “N/A”.

Work authorisation:

• United Kingdom (required)

Work Location: In person