At a Glance
- Tasks: Develop large-scale desktop applications using Java and Swing, focusing on real-world impact.
- Company: Join Semantics 21, a multi-award-winning software company making a difference in public safety.
- Benefits: Earn £35,000 to £45,000 with flexible hours, free parking, and opportunities for growth.
- Other info: Enjoy a friendly, low-bureaucracy environment with direct access to leadership.
- Why this job: Be part of a small team where your ideas shape innovative software solutions.
- Qualifications: Strong Java experience, especially in desktop applications, and problem-solving skills required.
The predicted salary is between 80000 - 80000 £ per year.
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 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.
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
- Supporting, mentoring, and where appropriate supervising other developers as the team grows
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
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 We're 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. Office-based preferred, though hybrid working may be considered depending on experience and role fit. Shortlisted candidates will be 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
£35,000 - £45,000 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. Direct applicants only - no recruitment agencies.
Senior Java Software Engineer - Desktop Applications in London employer: Semantics 21
At Semantics 21, we pride ourselves on being an excellent employer by fostering a collaborative and innovative work culture where every developer's ideas and contributions are valued. Our team enjoys the benefits of flexible working hours, direct access to leadership, and opportunities for professional growth within a supportive environment, all while working on impactful software that enhances public safety. Located in Stafford, our office provides a friendly atmosphere with free onsite parking, making it an ideal place for those looking to make a meaningful difference through their work.
StudySmarter Expert Advice🤫
We think this is how you could land Senior Java Software Engineer - Desktop Applications in London
✨Join Local Tech Meetups
Get out there and mingle with fellow developers by joining local tech meetups. It’s a fantastic way to meet people who might be working at Semantics 21 or know someone who does. Plus, you can pick up some trendy tech skills and trends while you're at it!
✨Contribute to Open Source Projects
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✨Tap into Online Developer Communities
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We think you need these skills to ace Senior Java Software Engineer - Desktop Applications in London
Some tips for your application 🫡
Show off your coding skills:When applying for a software engineering role, it's super important to showcase your coding skills. Make sure your CV includes your tech stack, any relevant programming languages you’re comfortable with, and examples of projects you've worked on. If you have a GitHub profile, link it up! We love to see code in action.
Tailor your portfolio:For a full-time role, we’d expect to see some solid examples of your work in your portfolio. Make sure to include at least two or three projects that highlight your problem-solving skills and your ability to work with different technologies. Focus on the projects that are most relevant to the position at Semantics 21.
Craft a killer cover letter:Your cover letter is your chance to stand out—make it personal! Explain why you want to work at Semantics 21 and how your skills align with the role. Show us your passion for software development. We dig enthusiastic candidates who understand the value of collaboration and continuous learning!
Be clear and concise:When it comes to writing your CV and cover letter, clarity is key. Avoid jargon that could confuse us and stick to simple, direct language. Highlight your achievements with quantifiable results where possible, and keep everything easy to read. A well-organised application goes a long way!
How to prepare for a job interview at Semantics 21
✨Brush Up on Your Coding Skills
For a full-time software engineering role, it's crucial that we stay sharp with our coding abilities. Expect technical questions that might involve solving problems on the spot or discussing algorithms. Practise on platforms like LeetCode or HackerRank to get comfortable with the types of questions that often come up.
✨Know Your Tools and Frameworks
Make sure we’re well-acquainted with the tools and technologies listed in the job description. Familiarise ourselves with any specific frameworks or programming languages mentioned. If Semantics 21 uses React or Node.js, for instance, be ready to discuss how we’ve used them in previous projects or coursework.
✨Showcase Your Projects
Bring along a portfolio that highlights our best work. This could be code samples, GitHub repositories, or any side projects we’ve built. Make sure we can talk through our thought process for each project, especially the challenges we faced and how we solved them—this shows our problem-solving skills in action.
✨Prepare for Behavioural Questions
While technical skills are key, full-time positions also require cultural fit. Be ready to discuss our previous experiences and how we handle teamwork, conflict, and deadlines. Brush up on the STAR method—Situation, Task, Action, Result—to clearly articulate our past experiences when discussing how we've contributed to a team.
